On sets of polynomials whose difference set contains no squares
Thái Hoàng Lê, Yuru Liu · Acta Arithmetica · 2013
Let ${\mathbb F}_q[t]$ be the polynomial ring over the finite field ${\mathbb F}_q$, and let ${\mathbb G_{N}}$ be the subset of ${\mathbb F}_q[t]$ containing all polynomials of degree strictly less than $N$. Define $D(N)$ to be the maximal cardinality of