On a class of $(\delta +\alpha u^2)$-constacyclic codes over ${\mathbb{F}}_q[u]/⟨u^4⟩$

Yuan Cao, Yonglin Cao, Jian Gao

Let ${\mathbb{F}}_q$ be a finite field of cardinality $q$, $R={\mathbb{F}}_q[u]/⟨u^4⟩={\mathbb{F}}_q+u{\mathbb{F}}_q+u^2{\mathbb{F}}_q+u^3{\mathbb{F}}_q$ $(u^4=0)$ whi…