Varieties of Lazy Magmas Characterized by Forbidden Substructure Theorems

João Araújo, Fernando Maia Ferreira, Michael Kinyon

A magma (or groupoid) is a set with a binary operation $(A,f)$. Roughly speaking, a magma is said to be lazy if compositions such as $f(x,f(f(y,z),u))$ depend on at most two variab…