Andrew D. King
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 Mar 14 comment Approximation to colouring for bounded degree graphs If chi(G) denotes the colouring number and not the chromatic number, you should change the notation -- maybe to col(G). Mar 12 awarded Yearling Feb 12 awarded Popular Question Feb 10 awarded Necromancer Aug 5 awarded Necromancer Apr 21 awarded Favorite Question Mar 12 awarded Yearling Mar 5 comment Linear intersection number and coloring (not chromatic) number What happens if you replace the colouring number with the minimum degree $+1$, or the maximum degree $+1$, or the chromatic number? Feb 12 comment Chromatic number of graphs of tangent closed balls A clarification: Choose the sphere $S$ to be smallest, and subject to that choose it to be extreme. I claim without proof that if a sphere kisses 12 others of equal or greater radius, then all 13 spheres have equal radius. Furthermore the sphere kissed by 12 others has its centre in the convex hull of the other 12 centres, and therefore is not extreme (of these 13 spheres) in any direction. Oct 31 awarded Nice Answer Oct 16 comment Is a rigid cycle a chordal graph? No to the second question, as exhibited by a graph on five vertices and eight edges with minimum degree 3. Jul 2 awarded Curious Mar 12 awarded Yearling Feb 6 comment Combinatorial Proof of Weak Perfect Graph Theorem. Thanks Petr, updated the link. Feb 6 revised Combinatorial Proof of Weak Perfect Graph Theorem. updated link Jan 8 comment How dense is the set of asymmetric graphs? Is there a simple justification for your first sentence? Dec 6 comment Expected Value for a Connected Graph It's easier to think about this in the equivalent model of giving each vertex a uniform random real in $[0,1]$. Nov 9 awarded Good Question Oct 1 answered Does the notion of graphs with vertex multiplicity exist? Jul 29 comment Hitting all cycles with three disjoint vertex sets Even any graph containing $K_4$ fails.