Ermelinda DeLaVina (delavinae@uhd.edu)
Next List | |||
Lower bounds for maximum number of leaves over all spanning trees, Ls(G) | |||
O | 2. | If G is a simple connected graph, then Ls(G) ≥ 2(average of l(v) - 1) | definitions reference |
1996 |
Next List | |||
Lower bounds on the bipartite number of simple connected graphs, b(G). | |||
O | 19. | If G is a simple connected graph, then b(G) ≥ FLOOR(average of ecc(v)+maximum of l(v)) | definitions |
July 3, 2003. June 22, 2005, note: if average of ecc(v) <= diam -1, then this conjecture follows from wowII #13. | |||
Next List |
Lower bounds on the path number of simple connected graphs, path(G). | |||
O | 34. | If G is a simple connected graph, then path(G) ≥ CEIL[distavg(C,V) + distavg(M,V)] | definitions |
July 15, 2003. | |||
Next List | |||
Lower bounds on the forest number of simple connected graphs, f(G). | |||
Note: |
Clearly b(G) ≥ f(G) ≥ path(G), and note that f(G)
and path(G) were not available to the program when lower bounds for b(G) were
generated. O (7), T(3), F(10) | ||
O | 40. | If G is a simple connected graph on more than one vertex, then f(G) ≥ CEIL[(p(G)+b(G)+1)/2] | definitions |
Mar 05, 2004. Mar 6, 2004, DeLaVina: For a connected graph on more than one vertex it is easily shown that f(G) ≥ b(G)/2 + 1. Thus, in the special case that path covering is one, the result follows. | |||
Next List | |||
2nd run on Lower bounds on the forest number of simple connected graphs, f(G). | |||
Note: |
Clearly b(G) ≥ f(G) ≥ tree(G) ≥ path(G), and note that
this (for the second run) time b(G), tree(G)
and path(G) were available to the program when lower bounds for f(G) were
generated;
Also for the second run for forest should reflect the counterexamples listed above
and now also includes the local independence invariants and the domination
number. conjectures 39 and, 47 were repeated with conjectures 57-67. | ||
O | 58. | If G is a simple connected graph, then f(G) ≥ CEIL[ b(G)/average of l(v)] | definitions |
Mar 25, 2004. This conjecture seems to be similar to conjecture 91. | |||
O | 59. | If G is a simple connected graph, then f(G) ≥ CEIL[sqrt[res(G)*b(G)]] | definitions |
Mar 25, 2004. | |||
O | 61. | If G is a simple connected graph, then f(G) ≥ res(G)+ CEIL[diam(G)/3] | definitions |
Mar 25, 2004. | |||
O | 63. | If G is a simple connected graph, then f(G) ≥ CEIL[(minimum of disteven(v) + b(G) + 1)/3] | definitions |
Mar 25, 2004. | |||
O | 64. | If G is a simple connected graph, then f(G) ≥ CEIL[(sqrt[a(G) * (1 + (n mod D(G))] ] | definitions |
Mar 25, 2004. | |||
O | 65. | If G is a simple connected graph, then f(G) ≥ distmin(A) + CEIL(distmin(M)/3], where A is the set of vertices of minimum degree and M is the set of vertices of maximum degree. | definitions |
Mar 25, 2004. | |||
O | 66. | If G is a simple connected graph, then f(G) ≥ 2*CEIL[even_modemin(G) /degavg(G)] | definitions |
Mar 25, 2004. | |||
Next List | |||
Lower bounds on the tree number of simple connected graphs, tree(G). | |||
Note: | Clearly b(G) ≥ f(G) ≥ tree(G) ≥ path(G). | ||
O | 72. | If G is a simple connected graph, then tree(G) ≥ CEIL[average of ecc(v) + maximum of l(v) /3] | definitions |
Apr 04, 2004. | |||
O | 76. | If G is a simple connected graph, then tree(G) ≥ freq[Tmax(v)]/FLOOR[degavg(G)] | definitions |
Apr 04, 2004. | |||
O | 84. | If G is a simple connected graph, then tree(G) ≥ 2rad(G)/d(G) | definitions |
Apr 04, 2004. | |||
O | 85. | If G is a simple connected graph, then tree(G) ≥ CEIL[sqrt(1 + 2*minimum of disteven(v))] | definitions |
Apr 04, 2004. | |||
Next List | |||
Upper bounds on the bipartite number of simple connected graphs, b(G). | |||
O | 91. | If G is a simple connected graph, then b(G) ≤ 1 + f(G) * (CEIL[average of l(v) ])/2 | definitions |
April 10, 2004. This conjecture seems to be similar to conjecture 58, but tighter for large b. | |||
Next List | |||
Upper bounds on the independence number of simple connected graphs, a(G). | |||
O | 96. | If G is a simple connected graph, then a(G) ≤ 1 + minimum disteven(v)*(maximum of l(v) -1) | definitions |
April 21, 2004. | |||
O | 100. | If G is a simple connected graph, then a(G) ≤ CEIL[(maximum of l(v) + 0.5*length(G))/2] | definitions |
April 21, 2004. |
|||
O | 103. | If G is a simple connected graph, then a(G) ≤ FLOOR[b(G) - LN[average of ecc(v)] | definitions |
April 21, 2004. July 2005, for large enough diameter this follows from the proposition listed below conjecture 17. | |||
O | 108. | If G is a simple connected graph, then a(G) ≤ maximum disteven(v) + 2*FLOOR[alphacore(G)/3] | definitions |
April 21, 2004. |
|||
O | 109. | If G is a simple connected graph, then a(G) ≤ FLOOR[(residue(G)+2b(G))/3] | definitions |
April 21, 2004. |
|||
O | 111. | If G is a simple connected graph, then a(G) ≤ CEIL[1 + |N(S)|* (average of l(v)- 1)], where S is the set of maximum degree vertices of the complement of the graph G the neighborhood is taken in the complement. | definitions |
April 21, 2004. |
|||
Lower bounds on the path number of simple connected graphs, path(G). #'s 31, 31a, and 35 were repeated from 1st run for path. | |||
O | 133. | If G is a simple connected graph, then path(G) ≥ rad(G)+ [average of l(v)]^cC4 | definitions |
July 12, 2005. | |||
O | 136. | If G is a simple connected graph, then path(G) ≥ (1+girth)/D(R) | definitions |
July 12, 2005. | |||
O | 137. | If G is a simple connected graph, then path(G) ≥ 4/p(G) | definitions |
July 12, 2005. | |||
O | 138. | If G is a simple connected graph, then path(G) ≥ (2+u(G))*distmin(M(G2)) | definitions |
July 12, 2005. | |||
2nd run for Lower bounds on the tree number of simple connected graphs, tree(G). See 68-85 for 1st run. Note: the program repeated some conjectures, but I do not repeat them here. | |||
Note: | Clearly b(G) ≥ f(G) ≥ tree(G) ≥ path(G). | ||
O | 141. | If G is a simple connected graph, then tree(G) ≥ (1/2)*girth - 1+ maximum of l(v) | definitions |
July 19, 2005. | |||
O | 142. | If G is a simple connected graph, then tree(G) ≥ (2/3)*girth + ecc(B) | definitions |
July 19, 2005. | |||
O | 143. | If G is a simple connected graph, then tree(G) ≥ (girth + 1)/σ(G) | definitions |
July 19, 2005. | |||
O | 144. | If G is a simple connected graph, then tree(G) ≥ girth -1 + ecc(Centers) | definitions |
July 19, 2005. | |||
O | 145. | If G is a simple connected graph, then tree(G) ≥ 2*ecc(B)/lmin(G) | definitions |
July 19, 2005. | |||
O | 146. | If G is a simple connected graph, then tree(G) ≥ 2*ecc(B)/rad(G2) | definitions |
July 19, 2005. | |||
Next List | |||
2nd Run for Lower bounds for maximum number
of leaves over all spanning trees, Ls(G) note: conjecture 5 was repeated from the first run for L. |
|||
O | 154. | If G is a simple connected graph, then Ls(G) ≥ (1 + maximum order of radial circles)/ minimum order of radial circles. | definitions |
Aug 8, 2005. Note that this conjecture proposes a sufficient condition for improvement of conjecture 5. | |||
O | 155. | If G is a simple connected graph, then Ls(G) ≥ 1 + number of distinct orders of radial circles. | definitions |
Aug 8, 2005. | |||
O | 157. | If G is a simple connected graph, then Ls(G) ≥ (f1(G) + SQRT[2* maximum {|E(R(v))|: v is a center of G] | definitions |
Aug 8, 2005. | |||
O | 160. | If G is a simple connected graph, then Ls(G) ≥ maximum of l(v) + maximum T(v)*cC4(G). | definitions |
Aug 8, 2005. | |||
O | 161. | If G is a simple connected graph, then Ls(G) ≥ maximum of l(v) of G . | definitions |
Aug 8, 2005. | |||
O | 162. | If G is a simple connected graph, then Ls(G) ≥ freq of minimum of l(v)*FLOOR[1 /d(G)]. | definitions |
Aug 8, 2005. | |||
O | 165. | If G is a simple connected graph, then Ls(G) ≥ CEIL[Sqrt[2*|N(M)-M|]], where M is the set of vertices of maximum degree. | definitions |
Aug 8, 2005. During the summer of 2005, the invariants Ls(G) and |N(M)-M| appeared in conjectures for Craig Foster's independent summer UHD student research project. The theme of those conjectures turned to the question is there a constant c such that Ls(G) ≥ c* |N(M)-M|. Craig's examples show that if a c exists, then c ≤ 1/4. He constructs graphs such that for k ≥ 1, L(G) = k + 2.and |N(M)-M| = 4k. | |||
O | 166. | If G is a simple connected graph, then Ls(G) ≥ |N(M)-M|]/SQRT[rad(G)], where M is the set of vertices of maximum degree. | definitions |
Aug 8, 2005. | |||
O | 169. | If G is a simple connected graph, then Ls(G) ≥ 1 + maximum of disteven(v) - minimum of disteven(v). | definitions |
Aug 8, 2005. | |||
O | 171. | If G is a simple connected graph, then Ls(G) ≥ (-1 + maximum of disteven(v) )/distavg(B), where B is the set of boundary vertices. | definitions |
Aug 8, 2005. | |||
O | 172. | If G is a simple connected graph, then Ls(G) ≥ -1 + D(B)+ distmin(M2), where B is the boundary and M2 is the set of maximum degree vertices of the second power graph of G. | definitions |
Aug 8, 2005. | |||
Lower bounds for Ls(G) + b(G) | |||
O | 174. | If G is a simple connected graph on at least 2 vertices, then Ls(G) + b(G) ≥ n + maximum of l(v) -1. | definitions reference |
Aug 8, 2005. Since 2a(G) ≥ b(G), if 174 is correct then Graffiti's #7 on wowII would follow from 174. See reference for proof of Ls(G) + b(G) ≥ n + CEIL[0.5*maximum of l(v)]. | |||
O | 176. | If G is a simple connected graph on at least 2 vertices, then Ls(G) + b(G) ≥ n + distmin(M2), where M2 is the set of vertices of maximum degree of G2. | definitions |
Aug 8, 2005. | |||
O | 177. | If G is a simple connected graph on at least 2 vertices, then Ls(G) + b(G) ≥ 2a(G) +σ(G). | definitions reference |
Aug 8, 2005. Waller proved that Ls(G) + b(G) ≥ 2a(G) + 1, see reference. | |||
O | 178. | If G is a simple connected graph on at least 2 vertices, then Ls(G) + b(G) ≥ maximum of l(v) + maximum of {|N(e)|: e an edge of G}. | definitions |
Aug 8, 2005. Note: Since Ls(G) ≥ maximum of {N(e): e an edge of G} -2 and b(G) ≥ maximum of l(v) + 1, it follows that Ls(G) + b(G) ≥ maximum of l(v) + maximum of {N(e): e an edge of G} -1, thus this conjecture proposes a slightly stronger bound that the one easily deduced. | |||
O | 179. | If G is a simple connected graph on at least 2 vertices, then Ls(G) + b(G) ≥ D(G) + domination(G) + maximum of l(v). | definitions |
Aug 8, 2005. | |||
O | 180. | If G is a simple connected graph on at least 2 vertices, then Ls(G) + b(G) ≥ 1 + a(G) + maximum of disteven(v) . | definitions |
Aug 8, 2005. | |||
O | 181. | If G is a simple connected graph on at least 2 vertices, then Ls(G) + b(G) ≥ a(G) + degavg(B(G2)) . | definitions |
Aug 8, 2005. | |||
O | 182. | If G is a simple connected graph on at least 2 vertices, then Ls(G) + b(G) ≥ D(B(G2)) + diam(G) . | definitions |
Aug 8, 2005. | |||
O | 183. | If G is a simple connected graph on at least 2 vertices, then Ls(G) + b(G) ≥ D(G2) + 2*rad(G2) . | definitions |
Aug 8, 2005. | |||
O | 184. | If G is a simple connected graph on at least 2 vertices, then Ls(G) + b(G) ≥ D(G2) + 2*distavg(B(G2),V(G2)) . | definitions |
Aug 8, 2005. | |||
O | 185. | If G is a simple connected graph on at least 2 vertices, then Ls(G) + b(G) ≥ D(G2) + 2*distavg(G2) . | definitions |
Aug 8, 2005. | |||
O | 186. | If G is a simple connected graph on at least 2 vertices, then Ls(G) + b(G) ≥ |N(C(G2))| + 2*ecc(C(G2)), where C(G2 ) is the set of center vertices of the second power graph.. | definitions |
Aug 8, 2005. | |||
Sophie Heuristic | |||
Sufficient conditions on a simple graph G for the existence of a Hamiltonian path (also known as Traceable graph) | |||
Note: the following conjectures were generated
by a new heuristic for G.pc named Sophie. The program was
queried for sufficient conditions for simple connected graphs on at least
two vertices.
| |||
O | 189. |
If G is a simple connected graph with n > 1 such that
maximum { disteven(v) : disteven(v) is the number of vertices at even distance from v } ≤ 1 + σ(G), then G has a Hamiltonian path. |
definitions |
Jan 12, 2006. | |||
O | 190. | If G is a simple connected graph with n > 1 such that 0.5(LS(G)+1) ≤ σ(G), then G has a Hamiltonian path. | definitions |
Jan 12, 2006. Note that
LS(G) = n -
gc.
where gc
is the connected domination number of G. Then this conjecture is
equivalent to
If G is a simple connected graph with n > 1 such that [n - gc+ 1]/2 ≤ σ(G), then G has a Hamiltonian path.
|
|||
O | 194. | If G is a simple connected graph with n > 1 such that a(G) ≤ 1 + λavg(G) , then G has a Hamiltonian path. | definitions |
Jan 12, 2006. | |||
O | 198a. | If G is a simple connected graph with n > 1 such that b(G) ≤ 2 + eccavg(G), then G has a Hamiltonian path. | definitions |
Jan 12, 2006. This too was eventually superseded. | |||
O | 199. | If G is a simple connected graph with n > 1 such that tree(G) - 2 ≤ κ(G), then G has a Hamiltonian path. | definitions |
Jan 12, 2006. | |||
O | 200. | If G is a simple connected graph with n > 1 such that tree(G) =CEIL[1 + λavg(G)], then G has a Hamiltonian path. | definitions |
Jan 12, 2006. | |||
O | 209. | If G is a simple connected graph with n > 1 such that (1/6)* [1 + (2)*|E(G)|] ≤ frequency of λmax(G), then G has a Hamiltonian path. | definitions |
Jan 12, 2006. | |||
O | 213. | If G is a simple connected graph with n > 1 such that 2 + the lower median of degree sequence of G ≤ g2 (G), then G has a Hamiltonian path. | definitions |
Jan 12, 2006. | |||
O | 217. | If G is a simple connected graph with n > 1 such that L(G) ≤ 4*cresidue=2(G) + 2, then G has a Hamiltonian path. | definitions |
Jan 12, 2006. | |||
Dalmatian Heuristic | |||
Lower bounds for Total Domination gt | |||
O | 232. |
If G is a simple connected graph, then
gt(G)
≥
0.5*[radius(G) + ecc(B)
] |
definitions |
Feb. 23, 2007. | |||
O | 233. |
If G is a simple connected graph, then
gt(G)
≥
(2/3) * (1+ecc(B)
) |
definitions reference |
Feb. 23, 2007. June 2007, in the reference it is proven that for a tree T, g(T) ≥ (1/2) * (1+ecc(B) ). A similar agreement for trees yields gt(T) ≥ (3/4) * (1+ecc(B) ). | |||
O | 235. |
If G is a simple connected graph, then
gt(G)
≥
(2/3)
ecc(B)
+ cbipartite(G). |
definitions |
Feb. 23, 2007. | |||
O | 241. |
If G is a tree, then
gt(G)
≥ FLOOR[number of components(<N[S]>)
+ distavg(C)], where <N[S]> is the subgraph induced by the closed
neighborhood of the set of vertices of degree two and C is the set of center
vertices. |
definitions |
Feb. 23, 2007. | |||
O | 242. |
If G is a tree, then
gt(G)
≥ (1/2)[number of components(<N[S]>
+ eccavg(G)], where <N[S]> is the subgraph induced by the closed
neighborhood of the set of vertices of degree two. |
definitions |
Feb. 23, 2007. | |||
O | 247. |
If G is a simple connected degree-regular graph, then
gt(G)
≥ 2*
p(G) |
definitions reference |
Feb. 23, 2007. May 2007: Qi Liu and Doug West proved this in case the degree is at most 3, see reference. | |||
O | 252. |
If G is a simple connected C4-free graph, then
gt(G)
≥ modemin(G) |
definitions |
Feb. 23, 2007. | |||
O* | 253. |
If G is a simple connected graph such that girth ≥
5, then
gt(G)
≥ 1 + modemin(G) |
definitions reference |
Feb. 23, 2007. In 2016 Desormeaux and Henning proved this this bound whenever girth ≥ 7 , see reference. | |||
O | 255. |
If G is a simple connected graph, then
gt(G)
≥ 2*|C|/[maximum of {N(e): e
an edge of G}], where
C is the set of vertices that are centers of G. |
definitions |
Feb. 23, 2007. | |||
O | 256. |
If G is a simple connected graph, then
gt(G)
≥ 2*|N(A)|/[maximum of {N(e):
e an edge of G}],
where A is the set of vertices of minimum degree. |
definitions |
Feb. 23, 2007. | |||
O | 258. |
If G is a simple connected graph, then
gt(G)
≥ 2*evenmax(G)/L(G), where
evenmax(G) = maximum {even(w) : even(w) = |{u : dist(w,u} is even}|}. |
definitions |
Feb. 23 , 2007. | |||
O | 259. |
If G is a simple connected graph, then
gt(G)
≥ 2*|N(M)-M|/L(G), where M is the
set of vertices of maximum degree. |
definitions |
Feb. 23, 2007. | |||
O | 260. |
If G is a simple connected graph, then
gt(G)
≥ 2*|N(B)-B|/L(G), where B is the
set of vertices of maximum maximum eccentricity. |
definitions |
Feb. 23, 2007. | |||
O | 261. |
If G is a simple connected graph, then
gt(G)
≥ 2*|N(S)-S|/L(G), where S is the
set of vertices of degree two. |
definitions |
Feb. 23, 2007. | |||
O | 267. |
If G is a simple connected graph such that girth(G) ≥
5, then
gt(G)
≥ CEIL[distavg(A,V)],
where A is the set of minimum degree vertices. |
definitions |
Feb. 23, 2007. | |||
O | 268. |
If G is a simple connected graph, then
gt(G)
≥ FLOOR[1+distavg(C)],
where C is the set of center vertices. |
definitions |
Feb. 23, 2007. | |||
O | 269. |
If G is a simple connected C4-free graph, then
gt(G)
≥ CEIL[1+distavg(C)],
where C is the set of center vertices. |
definitions |
Feb. 23, 2007. | |||
O | 271. |
If G is a simple connected graph, then
gt(G)
≥ CEIL[SQRT[2*distmax(M)]],
where M is the set of vertices of maximum degree. |
definitions |
Feb. 23, 2007. | |||
Dalmatian Heuristic | |||
Upper bounds for Total Domination gt | |||
O | 281. |
If G is a simple connected graph, then
gt(G) ≤
[frequency of
λmin(G)] + m(G) |
definitions |
Mar. 1, 2007. | |||
O | 287. |
If G is a simple connected graph, then
gt(G) ≤
k+ m(G),
where k is the first step in which a zero appears in the Havil-Hakimi process. |
definitions |
Mar. 1, 2007. | |||
O | 290. |
If G is a simple connected graph such that n(G)> 2, then
gt(G) ≤
k*D(G), where k
is the first step in which a zero appears in the Havil-Hakimi process. |
definitions |
Mar. 1, 2007. June 8, 2012, I believe I have an argument for maximum degree 3 and n at least 12. | |||
O | 291. |
If G is a simple connected graph, then
gt(G) ≤
k + frequency tmin(v),
where k is the first step in which a zero appears in the Havil-Hakimi process. |
definitions |
Mar. 1, 2007. | |||
O* | 298. |
If G is a simple connected graph, then
gt(G) ≤
annihilation(G)+ cC4(G). |
definitions |
Mar. 1, 2007.
It is not difficult to see that FLOOR(n(G)/2) £ annihilation(G) and it is known that if minimum degree is at least 3 then gt(G) ≤ n(G)/2. Thus, if minimum degree is at least three then gt(G) ≤ annihilation(G). From this we see that the only unsettled case is when minimum degree is at most 2, which includes trees. Note that for G a tree cC4(G) = 1, and the conjecture restricted to trees becomes gt(G) ≤ annihilation(G)+ 1 if G is a tree. Nov 2012, Desormeaux, Haynes and Henning proved that if G is a tree on n(G)³ 2, then gt(G) ≤ annihilation(G)+ 1, see [DHH]. [DHH] Wyatt J. Desormeaux, Teresa W. Haynes and Michael A. Henning, Relating the annihilation number and the total domination number of a tree, Discrete Applied Mathematics, article in press available online Oct 2012. |
|||
O | 299. |
If G is a simple connected graph, then
gt(G) ≤
annihilation(G)+ |S|, where S is the set of
vertices of degree two. |
definitions |
Mar. 1, 2007. | |||
O | 300. |
If G is a simple connected graph, then
gt(G) ≤
(1/2)*[n(G) + frequency of λmin(G)] |
definitions |
Mar. 1, 2007. | |||
O | 302. |
If G is a simple connected graph, then
gt(G) ≤
minimum of disteven(v) + frequency of λmax(G)) |
definitions |
Mar. 1, 2007. | |||
O | 304. |
If G is a simple connected graph, then
gt(G) ≤
(1/2)*[(frequency of λmax(G))
+ maximum of NG(e)] |
definitions |
Mar. 1, 2007. | |||
O | 305. |
If G is a simple connected graph, then
gt(G) ≤
CEIL[(2/3)*maximum of NG(e)] |
definitions |
Mar. 1, 2007. | |||
O | 308. |
If G is a simple connected graph, then
gt(G) ≤ (1/2)*[maxine(G)
+ minimum of NG(e)] |
definitions |
Mar. 1, 2007. | |||
O | 309. |
If G is a simple connected graph, then
gt(G) ≤ (1/2)*[maximum {disteven(v) - even horizontal(v): v in V(G)}
+ minimum of NG(e)] |
definitions |
Mar. 1, 2007. | |||
O | 310. |
If G is a simple connected graph, then
gt(G) ≤
CEIL[1 + Tdistmin(v)/3] |
definitions |
Mar. 1, 2007. | |||
Sophie Heuristic | |||
Sufficient conditions on a simple connected graphs for every minimal Total Dominating Set is a minimum Total Dominating Set. A graph with this property will be said to be Well Total Dominated. | |||
Note: the following conjectures were generated by a new heuristic for G.pc named Sophie. The program was queried for sufficient conditions for simple connected graphs on at least two vertices. | |||
O | 314. | Let G is a simple connected graph with n > 1. If G is triangle-free and path number ≤ 4, then G is well total dominated. | definitions |
Mar. 4, 2007. | |||
O | 315. | Let G is a simple connected graph with n > 1. Let P be the pendant vertices of G. If a(G) = |P|, then G is well total dominated. | definitions |
Mar. 4, 2007. | |||
O | 316. | Let G is a simple connected graph with n > 1. Let P be the pendant vertices of G. If |P| ≥ degavg(G), then G is well total dominated. | definitions |
Mar. 4, 2007. | |||
O | 317. | Let G is a simple connected graph with n > 1. If tree number ≥ |E(G)|, then G is well total dominated. | definitions |
Mar. 4, 2007. | |||
O | 318. | Let G is a simple connected graph with n > 1. If maximum disteven(v) ≥ |E(G)|, then G is well total dominated. | definitions |
Mar. 4, 2007. | |||
O | 319. | Let G is a simple connected graph with n > 1. If maximum disteven(v) = g(G), then G is well total dominated. | definitions |
Mar. 4, 2007. | |||
O | 320. | Let G is a simple connected graph with n > 1. If maximum disteven(v) = Tdistmin(G), then G is well total dominated. | definitions |
Mar. 4, 2007. | |||
O | 321. | Let G is a simple connected graph with n > 1. If eccavg(G) ≥ (1/3)*Tdistmax(G), then G is well total dominated. | definitions |
Mar. 4, 2007. | |||
O | 322. | Let G is a simple connected graph with n ≥ 5. If λmax(G) ≤ 1, then G is well total dominated. | definitions |
Mar. 4, 2007. | |||
O | 323. | Let G is a simple connected graph with n > 1. If maximum of {|NG(e)|: e an edge of G} ≤ 1 + maximum {distodd(v) - odd horizontal(v): v in V(G)}, then G is well total dominated. | definitions |
Mar. 4, 2007. | |||
O | 324. | Let G is a simple connected graph with n > 1. If maximum of {|NG(e)|: e an edge of G} ≤ 1 + residue(G), then G is well total dominated. | definitions |
Mar. 4, 2007. | |||
O | 325. | Let G is a simple connected graph with n > 1. If minimum of {|NG(e)|: e an edge of G} ≤ 1 + number of components of <N[S}> where S is the set of vertices of degree two, then G is well total dominated. | definitions |
Mar. 4, 2007. | |||
O | 326. | Let G is a simple connected graph with n > 1. If 3*m(G) ≤ |E(S)| where S is the set of vertices of degree two, then G is well total dominated. | definitions |
Mar. 4, 2007. | |||
O | 327. | Let G is a simple connected graph with n > 1. If 3*g(G) = gi(G), then G is well total dominated. | definitions |
Mar. 4, 2007. | |||
O | 328. | Let G is a simple connected graph with n > 1. If 4*m(G) ≤ frequency of maximum{K(v): K(v) is the number of K4 incident to a vertex v}, then G is well total dominated. | definitions |
Mar. 4, 2007. Note that if the graph has no K4, then the right hand side is n. | |||
Dalmatian Heuristic | |||
Upper bounds on Total Domination number gt of a Tree | |||
O | 340. | If T is a tree on n > 2 vertices, then γt ≤ number of components of <N(L) ∪ L> + modemin(T)* γ(T), where L is the set of leaves of T | definitions |
Feb. 18, 2009. | |||
O | 341. | If T is a tree on n > 2 vertices, then γt ≤ ⌈½A(T)⌉*σ(T) | definitions |
Feb. 18, 2009. | |||
O | 342. | If T is a tree on n > 2 vertices, then γt ≤ A(T) + ⌈half of number of isolates of <S(T)>⌉, where S(T) is the set of support vertices of T | definitions |
Feb. 18, 2009. | |||
O | 343. | If T is a tree on n > 2 vertices with degree 2 vertices, then γt ≤ A(T)+ ⌈half of number of components of <D2>⌉, where D2={v| deg(v) = 2} | definitions |
Feb. 18, 2009. | |||
O | 344. | If T is a tree on n > 2 vertices, then γt ≤ A(T) -1 + number of components of <N(L) ∪ L >, where L is the set of leaves of T | definitions |
Feb. 18, 2009. | |||
Dalmatian Heuristic | |||
Lower bounds on Total Domination number gt of a Tree | |||
O | 348. | If T is a tree on n>2 vertices, then γT(T) ≥ 2⁄3 |N(D2(T)) - D2(T)|, where D2={v| deg(v) = 2}. | definitions |
Feb. 18, 2009. | |||
O | 351. |
If T is a tree on n>2 vertices, then γT(T) ≥
number of components of <S(T) ∪ L
> + number of components of <N(D2(T)) ∪ D2(T)
>,
where S(T) is the set of support vertices, L is the set of leaves, and D2={v| deg(v) = 2}. |
definitions |
Feb. 18, 2009. | |||
O | 352. | If T is a tree on n>2 vertices, then γT(T) ≥ number of components of <N(D2(T)) ∪ D2(T) > + ⌈ ½ eccavg(M)⌉, where M is the set of vertices of maximum degree and D2={v| deg(v) = 2}. | definitions |
Feb. 18, 2009. | |||
O | 353. | If T is a tree on n>2 vertices, then γT(T) ≥ number of components of <D2(T) > + half of the order of a largest component of <M >, where D2={v| deg(v) = 2} and M is the set of vertices of maximum degree. | definitions |
Feb. 18, 2009. | |||
O | 354. | If T is a tree on n>2 vertices, then γT(T) ≥ ½|C| * number of components of <N(D2(T)) >, where D2={v| deg(v) = 2} and C is the set of all centers of T. | definitions |
Feb. 18, 2009. | |||
O | 356. | If T is a tree on n>2 vertices, then γT(T) ≥ |C|* distavg(L) , where C is the center of T and L is the set of leaves of T. | definitions |
Feb. 18, 2009. | |||
O | 358. | If T is a tree on n>2 vertices, then γT(T) ≥ ½ * ecc(C) + number of isolates of <S(T)> , where C is the center of T and S(T) is set of support vertices of T. | definitions |
Feb. 18, 2009. | |||
O | 359. | If T is a tree on n>2 vertices, then γT(T) ≥ ½ * ecc(C) + number of components of <S(T) ∪ L> , where C is the center of T, S(T) is set of support vertices of T and L is the set of leaves. | definitions |
Feb. 18, 2009. | |||
O | 360. | If T is a tree on n>2 vertices, then γT(T) ≥ number of components of <S(T) ∪ L> + ½ * distavg(C,V), where C is the center of T, S(T) is set of support vertices of T and L is the set of leaves. | definitions |
Feb. 18, 2009. | |||
O | 361. | If T is a tree on n>2 vertices, then γT(T) ≥ number of isolates of <S(T)> + |C|, where S(T) is the set of support vertices of T and C is the center of T. | definitions |
Feb. 18, 2009. | |||
O | 362. | If T is a tree on n>2 vertices, then γT(T) ≥ number of components of <S(T) ∪ L> + 1⁄3 * [1 + rad(T)], where S(T) is set of support vertices of T and L is the set of leaves. | definitions |
Feb. 18, 2009. | |||
O | 363. | If T is a tree on n>2 vertices, then γT(T) ≥ number of isolates of <S(T)> + ½ * distavg(B), where S(T) is the set of support vertices of T and B is the boundary of T. | definitions |
Feb. 18, 2009. | |||
O | 364. | If T is a tree on n>2 vertices, then γT(T) ≥ |S(T)| + ½ * |E(D2(T))|. | definitions |
Feb. 18, 2009. | |||
O | 365. | If T is a tree on n>2 vertices, then γT(T) ≥ number of isolates of <S(T)> + 1⁄3 * |E(D2(T))|. | definitions |
Feb. 18, 2009. | |||
O | 367. | If T is a tree on n>2 vertices such that the most frequently occurring degree is two, then γT(T) ≥ 4⁄3 *dd(T). | definitions |
Feb. 18, 2009. | |||
O | 369. | If T is a tree on n>2 vertices, then γT(T) ≥ ddmode(T) + (n mod 2)*k, where k corresponds to the kth step for a zero in the Havil-Hakimi process of a degree sequence. | definitions |
Feb. 18, 2009. | |||
O | 372. | If T is a tree on n>2 vertices, then γT(T) ≥ vc(T)/(p(T) - 1) | definitions |
Feb. 18, 2009. August 2009, similar to the argument above for Conjecture 371, when p(T) ≥ 3, the conjecture follows from γT(T) ≥ (2/3)(vc(T) +1). | |||
O | 373. | If T is a tree on n>2 vertices, then γT(T) ≥ 2⁄3 *distavg(B,V), where B is the set of vertices of maximum eccentricity | definitions |
Feb. 18, 2009. | |||
O | 374. | If T is a tree on n>2 vertices, then γT(T) ≥ distavg(B) + median(T) | definitions |
Feb. 18, 2009. | |||
O | 375. | If T is a tree on n>2 vertices, then γT(T) ≥ ecc(B) + lower median(T) | definitions |
Feb. 18, 2009. | |||
O | 376. | If T is a tree on n>2 vertices, then γT(T) ≥ number of isolates of <M> + |Dmin-total(T)|, where Dmin-total(T) = {v: Tdist(v) is minimum}. | definitions |
Feb. 18, 2009. | |||
O | 377. | If T is a tree on n>2 vertices, then γT(T) ≥ number of isolates of <M> + upper median(T). | definitions |
Feb. 18, 2009. | |||
O | 378. | If T is a tree on n>2 vertices, then γT(T) ≥ number of components of <M> + distavg(D2(T)). | definitions |
Feb. 18, 2009. | |||
O | 379. | If T is a tree on n>2 vertices, then γT(T) ≥ number of components of <M> + 1⁄3 *dd(T). | definitions |
Feb. 18, 2009. DPW: we can show that γT(T) ≥ number of components of <M> + 1. | |||
O | 380. | If T is a tree on n>2 vertices, then γT(T) ≥ |Deven(T)|/(ecc(C) - 1), where C is the center of T and Deven(T) is the set of vertices whose degree is an even number. | definitions |
Feb. 18, 2009. | |||
O | 381. | If T is a tree on n>2 vertices, then γT(T) ≥ number of isolates of <N(S(T))>/(Δ(S(T))-1), where S(T) is the set of support vertices. | definitions |
Feb. 18, 2009. | |||
Dalmatian Heuristic | |||
Upper bounds on 2-domination number g2 of a connected graph | |||
O | 382b. |
Let G be a connected graph n > 2 vertices.
γ2 ≤ -1 + a*(d + |A1|) , where d is the minimum degrees and A1 is the set of vertices that are adjacent to exactly one non-minimum degree vertex. |
definitions |
Jan. 2010. One case suggested
by this conjecture that doesn't follow from γ2
≤ 2a-ac
is the that when the graph has exactly one pendant and it is
not in the independence-core, γ2
≤ 2a -
1. |
|||
O | 382c. |
If G is a connected graph n > 2 vertices, then
γ2 ≤ [a*eccavg(A)+ |B|]/2, where A is the set of minimum degree vertices and B is the set of periphery vertices. |
definitions |
Jan. 2010. A special case of this would suggest a sufficient condition for γ2 ≤ a + |B|/2. Namely, if the minimum degree vertices have eccentricity two, then γ2 ≤ a + |B|/2. If the minimum degree vertices have eccentricity at least four then this follows from γ2 ≤ 2a.
|
|||
O | 382d. |
If G is a connected graph n > 2 vertices, then
γ2 ≤ [diam(G)(a+ |X|)]/2, where X is the set of vertices whose maximum local independence is maximum. |
definitions |
Jan. 2010. A special case of this would suggests that if the diameter of G is two, then γ2 ≤ a + |X|/2. If the diameter at least four then this follows from γ2 ≤ 2a.
|
|||
O | 382e. |
If G is a connected graph n > 2 vertices, then
γ2 ≤ Maxine + γ. |
definitions |
Jan. 2010. March 2010
DeLaVina & Larson observe that it is easily proven that γ2
≤ a+ γ.
|
|||
O | 387. |
If G is a connected graph on n > 2, then
γ2 ≤ n - m + 1. where m is the (upper) median of the degree sequence. |
definitions |
Jan. 2010. | |||
O | 391. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ ≤ p(G) + 1 + m(G[A2]) + |E(G[T])|, where A is the set vertices of degree two and T is the set of vertex of degree at least three. |
definitions |
Jan. 2010. | |||
Dalmatian Heuristic | |||
Upper bounds on 2-domination number g2 of a connected graph | |||
O | 382b. |
Let G be a connected graph n > 2 vertices.
γ2 ≤ -1 + a*(d + |A1|) , where d is the minimum degrees and A1 is the set of vertices that are adjacent to exactly one non-minimum degree vertex. |
definitions |
Jan. 2010. The only cases that do
not follow from γ2
≤ 2a
are when d=2
and
|A1| =
0,
or
d=1 and
|A1| =
1.
In either case, if the independence-core is not empty, γ2
≤ 2a-ac
≤ 2a -
1. Here is an
example
of a graph for which the conjectured relation is sharp,
d=1,
|A1| =
1
and ac=0.
|
|||
O | 382c. |
If G is a connected graph n > 2 vertices, then
γ2 ≤ [a*eccavg(A)+ |B|]/2, where A is the set of minimum degree vertices and B is the set of periphery vertices. |
definitions |
Jan. 2010. A special case of this would suggest a sufficient condition for γ2 ≤ a + |B|/2. Namely, if the minimum degree vertices have eccentricity two, then γ2 ≤ a + |B|/2. Here is an example of a graph for which the conjectured relation is sharp, there is one minimum degree vertex of eccentricity 2, d=3, |B| = 2, a=3, and γ2 = 4. If the average of the eccentricities of the minimum degree vertices is at least four then this follows from γ2 ≤ 2a.
|
|||
O | 382d. |
If G is a connected graph n > 2 vertices, then
γ2 ≤ [diam(G)(a+ |X|)]/2, where X is the set of vertices whose local independence is maximum. |
definitions |
Jan. 2010. A special case of this would suggests that if the diameter of G is two, then γ2 ≤ a + |X|. Here is an example of a graph for which the conjectured relation is sharp, diam(G) = 2, |X| = 1, a=3, and γ2 = 4. If the diameter at least four then this follows from γ2 ≤ 2a. |
|||
O | 382e. |
If G is a connected graph n > 2 vertices, then
γ2 ≤ Maxine + γ. |
definitions |
Jan. 2010. March 2010 DeLaVina, Larson & Pepper observe that it is easily proven that γk+1 - γk≤ a , from which one sees that γ2 ≤ a + γ. Later in [DLPW3] we proved that γa+b ≤ γa+ab, where is ab the b-independence number (the order of a largest subset of vertices that induces a subgraph with maximum degree at most b-1). | |||
O | 384b. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ FLOOR(n - |T |/2), where T = {k : some vertex of G has exactly k triangles incident to it}. |
definitions |
Jan. 2010. See an
example of
graph for which this is sharp and no other conjecture on this 2-domination
is sharp.
|
|||
O | 387. |
If G is a connected graph on n > 2, then
γ2 ≤ n - m + 1. where m is the (upper) median of the degree sequence. |
definitions |
Jan. 2010. May 2010 we have proved partial results on this; see [DLPW3]. | |||
O | 389a. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ |M|*(q + |A2|) -1, where A2 is the set vertices of degree at most two, M is the set of vertices of modemin degree and q is the 1st quartile degree . |
definitions |
Jan. 2010. | |||
O | 391. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ p(G) + 1 + m(G[T]) + |E(G[A3])|, where T is the set vertices of degree two and A3 is the set of vertices of degree at least three. |
definitions |
Jan. 2010. | |||
O | 392b. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ m(G[V - Ad ]) + |Ad | + |{v : |N(v) Ç A2 | = 1}| , where Ad is the set of vertices of minimum degree and A2 is the set of vertices of degree 2. |
definitions |
Jan. 2010. | |||
O | 392c. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ m(G[V - Ad ]) + |Ad | + kv(G), where Ad is the set of vertices of minimum degree and kv is the number of cut vertices. |
definitions |
Jan. 2010. Note: For trees this follows trivially since |V| ≤ m(G[V - L ]) + |L | + |V| - |L| = m(G[V - L ]) + |L | + kv(G). | |||
O | 392d. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ m(G) + m(G[V - N(N(P))]) + |Ad |, where Ad is the set of vertices of minimum degree and P is the set of pendants. |
definitions |
Jan. 2010. Note: If minimum degree is at least three, then this follows from conjecture 392a. | |||
O | 392e. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ m(G) + m(G[N(A2)]) + |Ad |, where Ad is the set of vertices of minimum degree and A2 is the set vertices of degree two. |
definitions |
Jan. 2010. Note: If minimum degree is at least three, then this follows immediately from conjecture 392a. | |||
O | 392f. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ m(G) + m(G[N(A2)]) + |{v : |N(v) Ç N(A) | = 1}|, where A is the set of vertices of minimum degree and A2 is the set vertices of degree two. |
definitions |
Jan. 2010. Note: If minimum
degree is at least three, then this follows from conjecture 392a.
|
|||
O | 393a. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ | V - N(N(P))| + m(G[N(N(P))]) + |P |, where P is the set of pendants. |
definitions |
Jan. 2010. Note: If minimum degree is greater than one, then this follows trivially. | |||
O | 393b. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ | V - N(N(P))| + |E(G[N(P)]) | + |{v : |N(v) Ç N(P) | = 1}|, where P is the set of pendants. |
definitions |
Jan. 2010. Note: If
minimum degree is greater than one, then this follows trivially.
|
|||
O | 393c. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ | V - N(N(P))| + |N(P) | + |{v : |N(v) Ç N[P] | = 1}|, where P is the set of pendants. |
definitions |
Jan. 2010. Note: If minimum degree is greater than one, then this follows trivially. | |||
O | 393d. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ µ(G[V - N(N(P))]) + a (G[V-M]) + |M4|, where P is the set of pendants, M is the set of maximum degree vertices and M4 is the set of vertices each of which is incident with the maximum number of K4. |
definitions |
Jan. 2010. Note: If
minimum degree is greater than one, then this follows trivially.
|
|||
O | 394. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ m(G) + |E(G[A2])| + |M |, where M is the set of vertices of min local independence and A2 is the set vertices of degree two. |
definitions |
Jan. 2010. | |||
O | 395a. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ |M| + m(G[V-Ad ]) + m(G[N(A2)]), where M is the set of vertices of modemin degree, Ad is the set of minimum degree vertices and A2 is the set vertices of degree two. |
definitions |
Jan. 2010. | |||
O | 395b. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ |M |+ d(G[V-A]) + |V-A3|, where M is the set of vertices of modemin degree, A is the set of minimum degree vertices and A3 is the set vertices of degree at least three. |
definitions |
Jan. 2010. | |||
O | 396. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ ddmode + |M | + |E(A3, V-A3)|, where M is the set of vertices of modemin degree and A3 is the set vertices of degree at least three. |
definitions |
Jan. 2010. | |||
O | 397c |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ |V - N(P)| + γ(G2), where P is the set of pendants. |
definitions |
Jan. 2010. If minimum degree
is greater than one, then this follows trivially.
|
|||
O | 398. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ |E(G[V - NN((P))])| + |{v : |N(v) Ç [V - N(P)] | = 1}| + |E(P,V-P)| , where P is the set of pendants. |
definitions |
Jan. 2010. Note: If minimum degree is greater than one, then this follows trivially. | |||
O* | 399a. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ WP(G) + FLOOR[a (G[C])/2], where C is the center. |
definitions |
Jan. 2010. Early in the
run for this batch of conjectures the program conjectured γ2
≤ WP(G)
+ 1 and later added 399a and 399b, which are attempts to suggest
sufficient conditions for when γ2
≤ WP(G). *May 2012, in [DP12] we proved that a2 ≤ WP(G) + 1, so here (since γ2 ≤ a2 ) it simply remains to settle γ2 ≤ WP(G) whenever the a (G[C]) = 1. [DP12] E. DeLaVina, R. Pepper, Graffiti.pc on the 2-independence number of a graph, preprint 2012. |
|||
O* | 399b. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ WP(G) + FLOOR[3/a (G[A3])], where A3 is the set vertices of degree at least three. |
definitions |
Jan. 2010. Early in the
run for this batch of conjectures the program conjectured γ2
≤ WP(G)
+ 1 and later added 399a and 399b, which are attempts to suggest
sufficient conditions for when γ2
≤ WP(G). *May 2012, in [DP12] we proved that a2 ≤ WP(G) + 1, so here (since γ2 ≤ a2 ) it simply remains to settle γ2 ≤ WP(G) whenever the a (G[A3]) ³ 4. [DP12] E. DeLaVina, R. Pepper, Graffiti.pc on the 2-independence number of a graph, preprint 2012. |
|||
O | 399c. |
If G is a connected graph on n > 2 vertices, then
γ2 ≤ (2/3)WP(G) + 2|M|, where M is the set vertices of minimum local independence. |
definitions |
Jan. 2010. | |||
O* | 400c. |
Let G be a connected graph on n > 2 vertices. Then γ2
≤ FLOOR[3A(G)
/dispmin],
where A(G) is the annihilation number . |
definitions |
Jan. 2010. Early in the
run for this batch of conjectures the program conjectured γ2
≤ A(G)
+ 1 and later added 400a, 400b and 400c which seem attempts to suggest
sufficient conditions for when γ2
≤ A. Feb. 2019, in [DHR14] Desormeaux et. al, proved that for trees the following holds γ2 ≤ A(G) + 1. [DHR14] Desormeaux WJ, Henning MA, Rall DF, Yeo A (2014) Relating the annihilation number and the 2-domination number of a tree. Discrete Math 319:15–23. |
definitions | ||
Jan. 2010. Early in the run for this batch of conjectures the program conjectured γ2 ≤ A(G) + 1 and later added 400a, 400b and 400c which seem attempts to suggest sufficient conditions for when γ2 ≤ A. | |||
O | 401a. |
Let G be a connected graph on n > 2 vertices. Then
γ2 ≤ 1+ FLOOR[Tdistmax/dispavg].
|
definitions |
Jan. 2010.
|
|||
O | 401b. |
Let G be a connected graph on n > 2 vertices. Then
γ2 ≤ FLOOR[3*Tdistmax / freq[Tmax(v)]]. |
definitions |
Jan. 2010.
|
|||
O | 402. |
Let G be a connected graph on n > 2 vertices. Then
γ2 ≤ 2[isolates(G[Ad ]) + |{v : |N(v) Ç AD | = 1}| + γt ] , where Ad is the set of vertices of minimum degree and AD is the set of maximum degree vertices. |
definitions |
Jan. 2010.
|
|||
Dalmatian Heuristic | |||
Bounds on sets related to H (the union of all maximum critical independent sets) for trees. | |||
O | 404. | Let G be a tree on n > 2 vertices and H the union of all maximum critical independent sets of G. Then number of peN(H) ≤ 2(|S|-1), where S is the set of support vertices of G. | definitions |
Jan. 2010. | |||
O | 405. | Let G be a tree on n > 2 vertices and H the union of all maximum critical independent sets of G. Then number of peN(H) ≤ 2a(G[V-L]), where L is the set of leaves of G. | definitions |
Jan. 2010. | |||
O | 406. | Let G be a tree on n > 2 vertices and H the union of all maximum critical independent sets of G. Then number of peN(H) ≤ peN(V-L) - 2, where L is the set of leaves of G. | definitions |
Jan. 2010. | |||
O | 407. | Let G be a tree on n > 2 vertices and H the union of all maximum critical independent sets of G. Then number of peN(H) ≤ 2p(G). | definitions |
Jan. 2010. | |||
Dalmatian Heuristic | |||
Upper Bounds on the order of H (the union of all maximum critical independent sets) for connected graphs. | |||
O | 410a. | Let G be a connected graph on n > 2; let A be the vertices of minimum degree, M the vertices of maximum degree, De the set of vertices that maximize the number of vertices at even distance and H the union of all maximum critical independent sets of G. Then |H| ≤ |V-A| + |V-M| + |E(G[De])|. | definitions |
June 2010. Since
n
≤|V-A|
+ |V-M| this and 410b are trivially true for non-regular
graphs. For regular graphs of degree greater than n/2, |H| = 0
and so the only open question is: if G is k-regular with k ≤ n/2, then |H| ≤ |E(G[De])|? |
|||
O | 410b. | Let G be a connected graph on n > 2; let A be the vertices of minimum degree, M the vertices of maximum degree, De the set of vertices that minimize the number of vertices at even distance and H the union of all maximum critical independent sets of G. Then |H| ≤ |V-A| + |V-M| + |E(G[De])|. | definitions |
June 2010. See the
comment on 410a and note that the only open question is: if G is k-regular with k ≤ n/2, then |H| ≤ |E(G[De])|? |
|||
Dalmatian Heuristic | |||
Lower Bounds on the order of H (the union of all maximum critical independent sets) for connected graphs. | |||
O | 412a. | Let G be a connected graph on n > 2 vertices, P the set of pendant vertices and H the union of all maximum critical independent sets of G. Then |H| ≥ cL(G[N(P)]) and if G is also bipartite then, |H| ≥ cL(G[N(P)]) + a(G[V-N(N(P))]). | definitions |
June 2010. The first part is easily true since P Í H and cL(G[N(P)]) £ |N(P)| £ |P|. | |||
O | 412b. | Let G be a connected graph on n > 2 vertices, P the set of pendant vertices, A2 the vertices of degree 2 and H the union of all maximum critical independent sets of G. Then |H| ≥ cL(G[N(P)]) and if G is also bipartite then, |H| ≥ cL(G[N(P)]) + a(G[A2]). | definitions |
June 2010. The first part is easily true since P Í H and cL(G[N(P)]) £ |N(P)| £ |P|. | |||
O | 412d. | Let G be a connected bipartite graph on n > 2 vertices and H the union of all maximum critical independent sets of G. Then |H| ≥ γT(G). | definitions |
June 2010. | |||
O | 412e. | Let G be a connected bipartite graph on n > 2 vertices, P the set of pendant vertices and H the union of all maximum critical independent sets of G. Then |H| ≥ 1 + D(G[N(N(P))]) | definitions |
June 2010. | |||
O | 412f. | Let G be a connected graph on n > 2 vertices, P the set of pendant vertices and H the union of all maximum critical independent sets of G. Then |H| ≥ m(G[V-N(P)]), and if G is also bipartite then, then |H| ≥ number of components of G[V-N(P] + m(G[V-N(P)]). | definitions |
June 2010. | |||
O | 413a. | Let G be a connected graph on n > 2 vertices, A the set of minimum degree vertices and H the union of all maximum critical independent sets of G. Then |H| ≥ k(G)*a(G[V-A]) + m(G[N(N(P))] | definitions |
June 2010. | |||
O | 413b. | Let G be a connected graph on n > 2 vertices, A2 the set of vertices of degree 2 and H the union of all maximum critical independent sets of G. Then |H| ≥ k(G)*cL(G[N(A2)-A2]) + pendants | definitions |
June 2010. | |||
O | 415a. | Let G be a connected graph on n > 2 vertices, A2 the set of vertices of degree 2 and H the union of all maximum critical independent sets of G. Then |H| ≥ (epN(A2) -1)*isolates(N(A2)). | definitions |
June 2010. | |||
O | 415b. | Let G be a connected graph on n > 2 vertices, A2 the set of vertices of degree 2, B2 the set of vertices of degree at most 2 and H the union of all maximum critical independent sets of G. Then |H| ≥ (epN(A2) -1)*isolates(B2). | definitions |
June 2010. | |||
O | 415c. | Let G be a connected graph on n > 2 vertices, B2 the set of vertices of degree at most 2 and H the union of all maximum critical independent sets of G. Then |H| ≥ (epN(B2) -1)*isolates(B2). | definitions |
June 2010. | |||
O | 416. | Let G be a connected graph on n > 2 vertices with diameter at most 2, P the set of pendants and H the union of all maximum critical independent sets of G. Then |H| ≥ isolates(N(N(P))) -2. | definitions |
June 2010. | |||
Dalmatian Heuristic | |||
Lower Bounds on the independent domination for connected graphs. | |||
O | 418b. |
Let G be a connected graph on n > 3 vertices, A the set of minimum degree
vertices of G. Then i(G)
£ a(G[V-A])
+ |E(G[N(A)])|*p(G). |
definitions |
Dec. 8 2010. If |E(G[N(A)])| = 0, then N(A) is an independent set. Take a maximal independent set of of G[V-A] containing N(A) and the claim follows. So suppose E(G[N(A)]) is not empty. If |A| -1 £ |E(G[N(A)])|*p(G), then the inequality follows from 418a. So suppose 0 < |E(G[N(A)])|*p(G) < |A| -1. | |||
O | 418c. |
Let G be a connected graph on n > 3 vertices, A the set of minimum degree
vertices of G. Then i(G)
£ a(G[V-A])
+ |E(G[N(A)])| + |A Ç Ic|.
|
definitions |
Dec. 8 2010. If |A| -1 £ |E(G[N(A)])| + |A Ç Ic|, then the inequality follows from 418a. So suppose 0 < |E(G[N(A)])|+ |A Ç Ic| < |A| -1. | |||
O | 420b. |
Let G be a connected graph on n > 3 vertices, A the set of minimum degree
vertices and S the set of support
vertices of G. Then i(G)
£ a(G[V(G)-N(S)])
+ 4(|E(G[N[A]])|-1). |
definitions |
Dec. 8 2010. Note if there are
so pendants then the equality follows trivially since in this case a(G[V(G)-N(S)])
= a(G). |
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O | 420c. |
Let G be a connected graph on n > 3 vertices, S the set of support
vertices of G and Tmin be the set of vertices incident with the
fewest triangles . Then i(G)
£ a(G[V(G)-N(S)])
+ 4(|Tmin|-1). |
definitions |
Dec. 8 2010. Note if there are
no pendants then the inequality follows trivially since in this case a(G[V(G)-N(S)])
= a(G); moreover, if the graph is triangle
free then again the inequality follows trivially
since 4(|Tmin|-1) = 4(n(G)-1). |
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O | 421b. |
Let G be a connected graph on n > 3 vertices and Ml
the vertices of maximum local independence. Then i(G)
£
g(G)FLOOR[0.5|Nmax(e)| -
1]. |
definitions |
Dec. 8 2010.
|
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O | 421c. |
Let G be a connected graph on n > 3 vertices and Ml
the vertices of maximum local independence. Then i(G)
£
g(G)(|N[Ml]| -
3). |
definitions |
Dec. 8 2010.
|
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O | 422a. |
Let G be a connected graph on n > 3 vertices and M the vertices of
maximum degree. Then i(G)
£
a(G[V-M)])+2FLOOR[E(G[M])/3]. |
definitions |
Dec. 8 2010.
|
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O | 422b. |
Let G be a connected graph on n > 3 vertices and M the vertices of
maximum degree. Then i(G)
£
a(G[M)])+g(G[V-M])2. |
definitions |
Dec. 8 2010.
|
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O | 422c. |
Let G be a connected graph on n > 3 vertices and A the vertices of
degree at most n/2. Then i(G)
£
a(G[A)])+2FLOOR[D(G[V-A])/3]. |
definitions |
Dec. 8 2010.
|
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O | 422d. |
Let G be a connected graph on n > 3 vertices and D the set of vertices
each of whose closed neighborhood contains the closed neighborhood of some other
vertex. Then i(G)
£
a(G[V-D])+FLOOR[(|E(G[D])|
+ 1)/3]. |
definitions |
Dec. 8 2010.
|
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O | 423. |
Let G be a connected graph on n > 3 vertices, M its set of maximum degree
vertices and A its set of minimum degree vertices. Then i(G)
£
|E(G[M])|+ a(G[N[A]])*a(G[V-A]). |
definitions |
Dec. 8 2010.
|
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O | 425d. |
Let G be a connected graph on n > 3 vertices and P the set of pendants of G. Then i(G)
£
|Tmin(G)|+
sum of K4(v))
+ g(G[V-N(P)]). |
definitions |
Dec. 8 2010. |
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O | 425e. |
Let G be a connected graph on n > 3 vertices and D the set of neighbor
dominators of G. Then i(G)
£
4|Tmin(G)|+
|E(G[D])| |
definitions |
Dec. 8 2010.
|
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O | 426. |
Let G be a connected graph on n > 3 vertices and M the vertices of
maximum degree. Then i(G)
£
n - g(G[N(M)]). |
definitions |
Dec. 8 2010.
|
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O | 427. |
Let G be a connected graph on n > 3 vertices and M the vertices of
maximum degree. Then i(G)
£
|E(C,V-C)| + FLOOR[(2/3)|E(G[V-N(P)])|]. |
definitions |
Dec. 8 2010.
|
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O | 430a. | Let G be a connected graph on n > 3 vertices and C the center of G. Then i(G) £ a(G[N(C)])+2*FLOOR[Caro-Wei -1] | definitions |
Dec. 8 2010.
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O | 430b. | Let G be a connected graph on n > 3 vertices and C the center of G. Then i(G) £ a(G[N(C)])*residue(G2)+isolates of G[V-M] | definitions |
Dec. 8 2010.
Jan
2011 DeLaVina see counterexample |
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O | 430c. | Let G be a connected graph on n > 3 vertices and C the center of G. Then i(G) £ lmax(G)*residue(G2)+ D(G[M]) | definitions |
Dec. 8 2010.
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O | 431a. | Let G be a connected graph on n > 3 vertices and D the set of vertices of degree two of G. Then i(G) £ residue(G)+ peN(N(D)) + |Tmin(G)|. | definitions |
Dec. 8 2010.
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O | 431b. | Let G be a connected graph on n > 3 vertices and A the set of vertices of minimum degree of G. Then i(G) £ residue(G)+ g(G[N[A]]) peN(N(D)) + dp(G), where dp(G) is the number pairs of vertices on the periphery at distance two. | definitions |
Dec. 8 2010.
|
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O | 431c. | Let G be a connected graph on n > 3 vertices. Then i(G) £ residue(G) * |Tmax(v)| + dd(G). | definitions |
Dec. 8 2010.
|
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O | 432a. | Let G be a connected graph on n > 3 vertices. Then i(G) £ annihilation number + minimum{vertices at even distance from v - vertices at odd distance from v}. | definitions |
Dec. 8 2010.
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O | 432b. | Let G be a connected graph on n > 3 vertices and P the set of pendants of G. Then i(G) £ |V-N(P)|+ minimum{vertices at even distance from v - vertices at odd distance from v}*_bipartite. | definitions |
Dec. 8 2010.
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O | 433. | Let G be a connected graph on n > 3 vertices and P the set of pendants of G. Then i(G) £ 0.5|N(M)|*FLOOR[2*sum of inverses of degrees of G2]. | definitions |
Dec. 8 2010.
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O | 434a. | Let G be a connected graph on n > 3 vertices and P the set of pendants of G. Then i(G) £ |M| + 2FLOOR[0.5*SW(Gc)]. | definitions |
Dec. 8 2010.
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O | 434a. | Let G be a connected graph on n > 3 vertices. Then i(G) £ |M| + 2FLOOR[0.5*SW(Gc)]. | definitions |
Dec. 8 2010.
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O | 434b. | Let G be a connected graph on n > 3 vertices and M the set of maximum degree vertices of G. Then i(G) £ d(G[M]) + 1 + SW(Gc). If diameter > 2, then i(G) £ d(G[M]) + SW(Gc). | definitions |
Dec. 8 2010.
|
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O | 434c. | Let G be a connected graph on n > 3 vertices and M the set of maximum degree vertices of G. Then i(G) £ d(G[V-M]) + 1 + SW(Gc). If d(G) = 1, then i(G) £ d(G[V-M]) + SW(Gc). | definitions |
Dec. 8 2010.
|
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O | 434d. | Let G be a connected graph on n > 3 vertices and B the set of vertices of maximum eccentricity of G. Then i(G) £ SW(Gc) - c(G[N[B]]) + 2, where c(G[N[B]]) is the number of components of G[N[B]]. | definitions |
Dec. 8 2010.
|
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O | 434e. | Let G be a connected graph on n > 3 vertices and C the center of G, i.e. the set of vertices of minimum eccentricity of G. Then i(G) £ SW(Gc) - ecc(C) + 2, where ecc(C) is the eccentricity of the set C. | definitions |
Dec. 8 2010.
|
|||
incomplete... | |||
Dalmatian Heuristic | |||
Upper Bounds on the 2-independence number for connected graphs. | |||
O | 435. | Let G be a connected graph on n > 3 vertices. Then a2(G)£ SW(G)+CEILING[(1+|E(G2[A])|/3], where SW(G) is the Szekeres-Wilf invariant of the complement graph of G and E(G2[A]) is the edge set of the subgraph of the second power graph of G induced by its minimum degree vertices of G2. | definitions |
Jan. 2012.
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O* | 436c. | Let G be a connected graph on n > 3 vertices. Then a2(G)£ k*WP(G) + D(G[D]), where D(G[D]) is the maximum degree of the subgraph induced by the neighbor dominators and k is the kth step for a zero in the Havil-Hakimi process. | definitions |
Jan. 2012. *May 2012, in [DP12] we proved that ak ≤ WP(G) + k-1, so here it simply remains to settle a2 ≤ WP(G) whenever the neigbor dominators are isolated in the subgraph that they induce and when k=1. [DP12] E. DeLaVina, R. Pepper, Graffiti.pc on the 2-independence number of a graph, preprint 2012. |
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O | 438a. | Let G be a connected graph on n > 3 vertices. Then a2(G)£ a(G) + a(G[V-A]) + |E(G[A])|, where A is the set of vertices of minimum degree of G. | definitions |
Jan. 2012. . | |||
O | 438b. | Let G be a connected graph on n > 3 vertices. Then a2(G)£ a(G) + a(G[V-H2]) + |E(G[H2])|, where H2 is the set of vertices of degree at most 2 in G. | definitions |
Jan. 2012. | |||
O | 439. | Let G be a connected graph on n > 3 vertices. Then a2(G)£ |N(M)| + FLOOR[2(CW(G) -1)], where M is the set of maximum degree vertices and CW(G) is the Caro-Wei invariant of G. | definitions |
Jan. 2012. | |||
O | 442. | Let G be a connected graph on n > 3 vertices. Then a2(G)£ n - CEILING[path(G[H3])/2, where H3 is the set of vertices of degree at least 3 in G. | definitions |
Jan. 2012. | |||
O | 443. | Let G be a connected graph on n > 3 vertices. Then a2(G)£ sum of disparities - |N(Ac)| -2, where Ac is the intersection of all maximum independent sets of G. | definitions |
Jan. 2012. | |||
O | 444. | Let G be a connected graph on n > 3 vertices. Then a2(G)£ n - FLOOR[dd(K4(v))/2], where dd(K4(v)) is the number of distinct values that appear in the sequence of the number of K4 incident to a vertex. | definitions |
Jan. 2012. | |||
O | 446. | Let G be a connected graph on n > 3 vertices. Then a2(G)£ pN(A) + |V\S|, where A is the set of minimum degree vertices and S is the set of support vertices. | definitions |
Jan. 2012. | |||
O | 448a. | Let G be a connected graph on n > 3 vertices. Then a2(G)£ |Hn/2| + |E(G[V-Hn/2])| + r(G), where Hn/2 is the set of vertices of degree greater than n/2 in G. | definitions |
Jan. 2012. | |||
O | 448b. | Let G be a connected graph on n > 3 vertices. Then a2(G)£ |V-A| + |E(G[N(S)])| + r(G), where A is the set of vertices of minimum degree and S is the set of support vertices in G. | definitions |
Jan. 2012. | |||
O | 449. | Let G be a connected graph on n > 3 vertices. Then a2(G)£ |V\H3| + CEILING[(|E(G[H3])|-1)/2], where H3 is the set of vertices of degree at least 3. | definitions |
Jan. 2012. | |||
O | 450. | Let G be a connected graph on n > 3 vertices. Then a2(G)£ pN(A2) + |V\S| + pN(V\H3), where A2 is the set of degree two vertices, S is the set of support vertices and H3 is the set of vertices of degree at least 3. | definitions |
Jan. 2012. | |||
| |||
Dalmatian Heuristic | |||
Lower Bounds on the 2-independence number for connected graphs. | |||