ABSTRACT. Having an MV-algebra, we can restrict its binary operation addition only to the pairs of orthogonal elements. The resulting structure is known as an effect algebra, precisely distributive lattice effect algebra. Basic algebras were introduced as a generalization of MV-algebras. Hence, there is a natural question what an effect-like algebra can be reached by the above mentioned construction if an MV-algebra is replaced by a basic algebra. This is answered in the paper and properties of these effect-like algebras are studied. . An effect algebra is a partial algebra which serves as a generalization of the set of Hilbert-space effects, i.e. self-adjoint operators on a Hilbert space (see e.g.[11] for the motivation in full details). For reader's convenience, we recall the definition of effect algebra.
Ò Ø ÓÒ 1ºAn effect algebra is a partial algebra E = (E; +, 0, 1) of type (2, 0, 0) satisfying the axioms (EA1) if x + y is defined then y + x is defined and x + y = y + x; (EA2) if x + y and (x + y) + z are defined then y + z and x + (y + z) are defined and x + (y + z) = (x + y) + z;(EA3) for each a ∈ E there exists a unique b ∈ E such that a + b = 1; let us denote this b by a ; (EA4) if 1 + a is defined then a = 0.2000 M a t h e m a t i c s S u b j e c t C l a s s i f i c a t i o n: Primary 06B05, 06B15, 06D35, 06D30, 03G25, 03G10, 06A12. K e y w o r d s: effect algebra, MV-algebra, basic algebra, weak effect algebra, commutative weak effect algebra.