Written on the Wall II

Ermelinda DeLaVina (delavinae@uhd.edu)

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   Lower bounds for maximum number of leaves over all spanning trees, Ls(G) 
    
O2. If G is a simple connected graph, then Ls(G) ≥ 2(average of l(v) - 1)definitions reference
   1996  
     
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   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.    
    
     
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    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.  
    
   
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  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. 
       
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  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.   
   
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  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. 
   
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   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.  
   
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   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. 
     
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    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) ≥ 23 |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>  + 13 * [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)>  + 13 * |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) ≥  43 *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) ≥  23 *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>  + 13 *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).
 
     
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).
 
     
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.
 
     
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.
 
     
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.
 
     
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.
 
     
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.
 
     
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.
 
     
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.
 
     
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.

 
 
     
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.



 
 
     
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.
 
     
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.
 
     
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.


 
 
     
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
 
 
     
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.  

 
 
     
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.  
 
 
     
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.  
 
 
     
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.  
 
 
     
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.  
 
 
     
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.  
 
 
     
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.  
 
 
     
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.

 
 
     
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.

 
 
     
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.
 
 
     
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.
 
 
     
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.
 
 
     
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.

 

 
     
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.

 
     
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.