Esmaeil Parsa

collaborators

2 papers

math.CO2021

On random digraphs and cores

Esmaeil Parsa, P. Mark Kayll

An acyclic homomorphism of a digraph $C$ to a digraph $D$ is a function $ρ : V (C) \to V (D)$ such that for every arc $uv$ of $C$ , either $ρ (u) = ρ (v)$ , or $ρ (u) ρ (v)$ is an arc of $…

math.CO2020

Uniquely $D$ -colourable digraphs with large girth II: simplification via generalization

P. Mark Kayll, Esmaeil Parsa

We prove that for every digraph $D$ and every choice of positive integers $k$ , $ℓ$ there exists a digraph $D^{*}$ with girth at least $ℓ$ together with a surjective acyclic hom…

On random digraphs and cores

Uniquely D-colourable digraphs with large girth II: simplification via generalization

Uniquely $D$ -colourable digraphs with large girth II: simplification via generalization