Let $\Avar_n$ and $\VV_n$ be the varieties generated by all $n$-element additively idempotent semirings (ai-semirings) and all $n$-element semirings with commutative addition, respectively, in the signature $(+,\cdot)$ without constants. We prove that both varieties are finitely based if and only if $n\leq2$. The five-element case follows from cyclic identities and a structural analysis of products of squares. For $n\geq6$, each variety contains a finite inherently nonfinitely based ai-semiring. We also prove $\VV_n\cap\AI=\Avar_n$ for every $n$, where $\AI$ is the variety of all ai-semirings.
From subtractive ideals of semirings to deductive and inductive sets in general algebras
National Institute for Theoretical and Computational Sciences(国家理论与计算科学研究所);Department of Mathematics and Applied Mathematics, University of Johannesburg(约翰内斯堡大学数学与应用数学系);Mathematics Division, Department of Mathematical Sciences, Stellenbosch University(斯坦陵布什大学数学科学系数学分部);Department of Computing, Mathematical, and Statistical Sciences, University of Namibia(纳米比亚大学计算、数学与统计科学系)
Finite Structure and Radical Theory of Commutative Ternary $Γ$-Semirings
Department of Mathematics, Government College (Autonomous), Y-Junction, Rajahmundry, 533105, A.P.,India(政府学院(自治),Y交汇处,拉贾穆恩德里);Department of Mathematics, Acharya Nagarjuna University, Pedakakani, Guntur, 522510, A.P., India(阿查里亚·纳加尔琼纳大学);Department of Mathematics, Government College For Women (A), Pattabhipuram, Guntur, 522006, A.P., India(女子政府学院(A))