# ZarankiewiczDB,

an online database of Zarankiewicz numbers.

### Matrix for z(4,4 | 4,4)

 $I$ $I$ $I$ $\alpha$ $I$ $\beta$ $\alpha\beta$ $I$ $\alpha\beta$ $I$ $\beta$ $I$ $\beta$ $\alpha\beta$ $I$ $I$

$I$ is the identity, and $\alpha,\beta$ generate $\mathbb{Z}_2 \times \mathbb{Z}_2$. The $I$ entries form an extremal rectangle-free matrix, showing that the finite projective plane of order 4 is sub-similar.

weight = 64, submitted by Andrew Kay on April 22nd, 2016 (link, raw)