New posts in Graph Theory

How many different figures can be formed with a regular polygon of $n$ vertices and a number $d$ of diagonals of this polygon?

black and white grid

Find the maximum number of draws in a tournament.

Example of a proper class of graphs for which no member is isomorphic to an induced subgraph of a different member?

Do there exist asymmetric hamiltonian graphs?

Prove that a tree with a vertex $v$ of degree $k > 1$ has at least $k$ leaves

Binomial upper bound for the bi-color Ramsey numbers (Erdős-Szekeres)

A graph with radius three and diameter four.

If all subgraphs of two graphs are pairwise isomorphic, are the graphs themselves isomorphic?

In a club with 99 people, everyone knows at least 67 people. Prove there's a group of 4 people where everyone knows each other