David Roberson's user avatar
David Roberson's user avatar
David Roberson's user avatar
David Roberson
  • Member for 12 years, 5 months
  • Last seen this week
9 votes

Spectrum of orthogonality graph (2)

9 votes
Accepted

Computer program for counting graph homomorphisms

8 votes

Graph homomorphisms and line graph

8 votes

Finite sets of vectors closed under an orthogonality property

7 votes
Accepted

Projective graphs

6 votes
Accepted

Does the clique-coclique bound hold for all walk-regular graphs?

5 votes
Accepted

Infinite graph with lots of non-isomorphic induced subgraphs

5 votes

The chromatic number of a Hamming-related graph

5 votes

A graph spectra problem?

4 votes
Accepted

Infinite connected $k$-regular graphs

4 votes

How do eigenvalues of combinatorial Laplacian relates to automorphisms in graphs?

4 votes

Vector chromatic number and Lovasz theta

4 votes

Does there exist a nontrivial perfect group with a "locally commuting" presentation?

4 votes
Accepted

Contracting non-adjacent points in the icosahedron

3 votes

Do graphs with $\omega(G) = \chi(G)$ grow "common" as $|V|$ grows large?

3 votes
Accepted

Commutative graph product with multiplicative independence number?

3 votes
Accepted

Product of critical graphs and Hedetniemi's conjecture

2 votes
Accepted

Critical graphs and endomorphisms

2 votes
Accepted

Co-spectral fractional isomorphic graphs with different Laplacian spectrum

2 votes

The bipartite double of two regular graphs

2 votes

If two vertices induce isomorphic subgraphs when they are removed, are they conjugate?

2 votes
Accepted

Homomorphisms relationship with Graph Degeneracy

1 vote

SDP relaxation vs LP relaxation

1 vote

Triange-free graph and its complement has Lovász number > 3

1 vote
Accepted

Largest edge set compatible with graph endomorphisms

0 votes

ILP for minimum edge coloring problem