Let be a nonempty set together with three binary operations: , and . The set is called a trisemigroup if the following two properties hold:
For each , is a semigroup.
The three binary operations , and satisfy the Hu-Liu triassociative law :
(1) |
(2) |
(3) |
(4) |
(5) |
for all .
We say that a monoid is 2-cancellative with respect to a generating set when it has cancellation on monomials of length 2 in the generators in the sense:
For (as just described) let be the unique solution for to the equation
(11) |
Define the commutator and the associator by:
The associator subloop is .
An element of a loop is a weak inverse property (WIP) element iff for all ,
Let denote the set of all WIP elements of Q.
Define on by