Joins and Direct Products of Equational Classes
- 1 January 1969
- journal article
- Published by Canadian Mathematical Society in Canadian Mathematical Bulletin
- Vol. 12 (6) , 741-744
- https://doi.org/10.4153/cmb-1969-095-x
Abstract
Let K0 and K1 be equational classes of algebras of the same type. The smallest equational class K containing K0 and K1 is the join of K0 and K1; in notation, K = K0 ∨ K1. The direct product K0 × K1 is the class of all algebras α which are isomorphic to an algebra of the form a0 × a1, a0 ∈ K1. Naturally, K0 × K1 ⊆ K0 ∨ K1, Our first theorem states a very simple condition under which K0 × K1 = K0 ∨ K1, and an additional condition under which the representation α ∨ a0 × a1 unique.Keywords
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