Algebra has permutable congruences iff it satisfies Malcev term m(x,x,y) = y, m(x,y,y) = x. Equivalent to: congruences commute Θ_1 ∘ Θ_2 = Θ_2 ∘ Θ_1. Groups, rings have Malcev term. Foundation of universal-algebraic classification.
Algebra has permutable congruences iff it satisfies Malcev term m(x,x,y) = y, m(x,y,y) = x. Equivalent to: congruences commute Θ_1 ∘ Θ_2 = Θ_2 ∘ Θ_1. Groups, rings have Malcev term. Foundation of universal-algebraic classification.