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Leen Droogendijk
  • Member for 8 years, 9 months
  • Last seen more than a week ago
  • Vianen, the Netherlands
5 votes
0 answers
360 views

Unimodality of chromatic polynomial

5 votes
2 answers
1k views

A triangle-free, 6-chromatic graph with 44 vertices

4 votes
1 answer
199 views

Cyclic Golomb ruler

4 votes
1 answer
270 views

$\alpha$-critical graphs and chordless odd cycles

3 votes
1 answer
373 views

A longest cycle in a 3-connected graph has a chord

3 votes
1 answer
57 views

Given positive integers $a,b,n,t$ with $n>t$ and the relations $n-1=a(t-1)$ and $an=bt$, prove that $b>t$.

3 votes
1 answer
52 views

Question about uniquely colorable graphs

3 votes
0 answers
123 views

Chromatic number of the pancake graph

3 votes
1 answer
129 views

Chromatic number of the pancake graph is subadditive

2 votes
0 answers
69 views

The simultaneous gossip problem

2 votes
1 answer
83 views

Covering one part of a bipartite set

2 votes
1 answer
66 views

Geometric thickness of $K_{15}$.

1 vote
1 answer
85 views

Is this graph a graceful tree?

1 vote
1 answer
57 views

Unifying polynomials

1 vote
0 answers
28 views

"Mobility" in graphs

0 votes
0 answers
19 views

Dynkin diagrams and graphs with spectral radius at most 2

0 votes
1 answer
42 views

Pancake problem