Every additively idempotent semiring satisfying $xy\approx xz$ is finitely based

Abstract

We study the finite basis problem for additively idempotent semirings satisfying the identity $xy\approx xz$. Let $\mathbf{R}$ denote the variety of all such semirings. Yue et al. (2025, Algebra Universalis, DOI:10.1007/s00012-025-00908-5) established that $\mathbf{R}$ is finitely generated. In this paper, we show that the subvariety lattice of $\mathbf{R}$ forms a distributive lattice of order $10$. As a consequence, the variety $\mathbf{R}$ is a Cross variety, and every member of $\mathbf{R}$ is finitely based.