This page contains the multiplication tables of the inverse semigroups of order
at most 12. This data was originally make available by
Martin E. Malandro on his
webpage based on the
method described in the paper:

Martin E. Malandro, ‘Enumeration of finite inverse semigroups’,
preprint; https://arxiv.org/abs/1312.7192

The data was converted into a compressed format by Chris Russell. The tables in
the linked files can be read into GAP
using the function `ReadMultiplicationTable`

in the
Semigroups package
version 3.1.0 or higher.

The files on this page are available gzipped
and xzipped since the latter provides
better compression in some cases.

The sequence of numbers of inverse semigroups up to isomorphism is
A001428 on the OEIS.

## inverse semigroup by order...

## inverse semigroup of size 2 by number of idempotents...

## inverse semigroup of size 3 by number of idempotents...

## inverse semigroup of size 4 by number of idempotents...

## inverse semigroup of size 5 by number of idempotents...

## inverse semigroup of size 6 by number of idempotents...

## inverse semigroup of size 7 by number of idempotents...

## inverse semigroup of size 8 by number of idempotents...

## inverse semigroup of size 9 by number of idempotents...

## inverse semigroup of size 10 by number of idempotents...

## inverse semigroup of size 11 by number of idempotents...

## inverse semigroup of size 12 by number of idempotents...