Article
Keywords:
difference semigroups; identities; semigroup reducts; subtraction semigroups; subtraction algebra; Boolean algebra
Summary:
A subtraction semigroup is a semigroup $(A,\ldotp,-)$ with a further operation "$-$" added, called subtraction and satisfying certain axioms. The paper concerns a problem by B. M. Schein concerning the structure of multiplication in a subtraction semigroup.