Polynomial-Time Tests for Difference Terms in Idempotent Varieties

William Demeo, Ralph Freese, Matthew Valeriote
2019 International journal of algebra and computation  
We consider the following practical question: given a finite algebra A in a finite language, can we efficiently decide whether the variety generated by A has a difference term? We answer this question (positively) in the idempotent case and then describe algorithms for constructing difference term operations.
doi:10.1142/s021819671950036x fatcat:p5wehl2zj5b27ckcc3qgfw5nui