2-D SKEW CONSTACYCLIC CODES OVER R[x, y; ρ, θ]

For a finite field fq, the bivariate skew polynomial ring fq[x, y; ρ, θ] has been used to study codes [25]. in this paper, we give some characterizations of the ring r[x, y; ρ, θ], where r is a commutative ring. we investigate 2-d skew (λ1, λ2)-constacyclic codes in the ring r[x, y; ρ, θ]/l . also, the dual of 2-d skew (λ1, λ2)-constacyclic codes is investigated.