A Generalization of the Methods of Brass, Harboth, and Nieborg

Brendon Stanton

In 1995, Brass, Harborth and Nienborg disproved a conjecture of Erdős when they showed that a $C_4$-free subgraph of the hypercube, $Q_n$, can have at least $(\frac 12 +ω(1))e(Q_n)…