Bounds on the number of autotopisms and subsquares of a Latin square

Abstract

A subsquare of a Latin square L is a submatrix that is also a Latin square. An autotopism of L is a triplet of permutations (α, β, γ) such that L is unchanged after the rows are permuted by α, the columns are permuted by β and the symbols are permuted by γ. Let n!(n−1)!R _n be the number of n×n Latin squares. We show that an n×n Latin square has at most n ^{O(log k)} subsquares of order k and admits at most n ^{O(log n)} autotopisms. This enables us to show that {ie11-1} divides R _n for all primes p. We also extend a theorem by McKay and Wanless that gave a factorial divisor of R _n , and give a new proof that R _p ≠1 (mod p) for prime p.