MathCastle
Graph TheoryChallengeIsomorphism and Subgraphs

Isomorphism and Subgraphs · Challenge problem

The 33-dimensional hypercube Q3Q_3 has vertices {0,1}3\{0,1\}^3 with an edge between strings differing in exactly one coordinate (1212 edges total). How many 44-element subsets of its 88 vertices induce a subgraph isomorphic to C4C_4?