Abstract
In this paper it is shown how the graphical methods developed
by Stephen for analyzing inverse semigroup presentations may be
used to study varieties of inverse semigroups. In particular, these methods
may be used to solve the word problem for the free objects in the variety
of inverse semigroups generated by the five-element combinatorial Brandt
semigroup and in the variety of inverse semigroups determined by laws of
the form x
n
= x
n+l
. Covering space methods are used to study the free
objects in a variety of the form V \l Q where V is a variety of inverse
semigroups and Q is the variety of groups.
| Original language | American English |
|---|---|
| Pages (from-to) | 1084-1097 |
| Journal | Canadian Journal of Mathematics |
| Volume | 42 |
| Issue number | 6 |
| State | Published - 1990 |