Problem Statement
If $G$ is a random graph on $2^d$ vertices, including each edge with probability $1/2$, then $G$ almost surely contains a copy of $Q_d$ (the $d$-dimensional hypercube with $2^d$ vertices and $d2^{d-1}$ many edges).
Categories:
Graph Theory
Progress
A conjecture of Erdős and Bollobás. Solved by Riordan [Ri00], who in fact proved this with any edge-probability $>1/4$, and proves that the number of copies of $Q_d$ is normally distributed.See also the entry in the graphs problem collection.
Source: erdosproblems.com/578 | Last verified: January 15, 2026