<TitlePage>
  <Title>&Semigroups;</Title>
  <Version>Version &VERSION;</Version>

  <Author>J. D. Mitchell
    <Email>jdm3@st-and.ac.uk</Email>
    <Homepage>http://tinyurl.com/jdmitchell</Homepage>
  </Author>
  
  <Author>Manuel Delgado</Author>
  <Author>James East</Author>
  <Author>Attila Egri-Nagy</Author>
  <Author>Nicholas Ham</Author>
  <Author>Julius Jonu&#353;as</Author>
  <Author>Markus Pfeiffer</Author>
  <Author>Ben Steinberg</Author>
  <Author>Jhevon Smith</Author>
  <Author>Michael Torpey</Author>
  <Author>Wilf Wilson</Author>

  <Copyright>&copyright; &COPYRIGHTYEARS; by J. D. Mitchell et al.<P/>
    &Semigroups; is free software; you can redistribute it and/or modify it
    under the terms of the <URL Text="GNU General Public License">
    http://www.fsf.org/licenses/gpl.html</URL> as published by the Free Software
    Foundation; either version 3 of the License, or (at your option) any later
    version.
  </Copyright>

  <Abstract>
    The &Semigroups; package is a &GAP; package containing methods for
    semigroups, monoids, and inverse semigroups, principally of
    transformations, partial permutations, bipartitions, subsemigroups of
    regular Rees 0-matrix semigroups, free inverse semigroups, free bands, and
    semigroups of matrices over finite fields. 
    <P/>
    
    &Semigroups; contains more efficient methods than those available in the
    &GAP; library (and in many cases more efficient than any other software)
    for creating semigroups, monoids, and inverse semigroup, calculating their
    Green's structure, ideals, size, elements, group of units, small generating
    sets, testing membership, finding the inverses of a regular element,
    factorizing elements over the generators, and many more. It is also
    possible to test if a semigroup satisfies a particular property, such as if
    it is regular, simple, inverse, completely regular, and a variety of
    further properties.
    <P/>
    
    There are methods for finding congruences of certain types of semigroups,
    the normalizer of a semigroup in a permutation group, the maximal
    subsemigroups of a finite semigroup, and smaller degree partial permutation
    representations and the character tables of inverse semigroups. There are
    functions for producing pictures of the Green's structure of a semigroup,
    and for drawing bipartitions. 
  </Abstract>

  <Acknowledgements>
    I would like to thank P. von Bunau, A. Distler, S. Linton, C. Nehaniv,  J.
    Neubueser, M. R. Quick, E. F. Robertson, and N. Ruskuc for their help and
    suggestions.  Special thanks go to J. Araujo for his mathematical
    suggestions and to M. Neunhoeffer for his invaluable help in improving the
    efficiency of the package. 
    <P/>

    Manuel Delgado and Attila Egri-Nagy contributed to the functions
    <Ref Func="Splash"/> and <Ref Oper="DotDClasses"/>.
    <P/>
      
    James East, Attila Egri-Nagy, and Markus Pfeiffer contributed to the part of
    the package relating to bipartitions. I would like to thank the University
    of Western Sydney for their support of the development of this part of the
    package.
    <P/>

    Nick Ham contributed many of the standard examples of bipartition
    semigroups.
    <P/>

    Julius Jonu&#353;as contributed the part of the package relating to free
    inverse semigroups, and contributed to the code for ideals.
    <P/>
    
    Yann Peresse and Yanhui Wang contributed to the function <Ref
      Oper="MunnSemigroup"/>.
    <P/>

    Jhevon Smith and Ben Steinberg contributed the function 
    <Ref Attr="CharacterTableOfInverseSemigroup"/>.
    <P/>

    Michael Torpey contributed the part of the package relating to congruences
    of Rees (0-)matrix semigroups.
    <P/>

    Wilf Wilson contributed to the part of the package relating maximal
    subsemigroups and smaller degree partial permutation representations of
    inverse semigroups. We are also grateful to C. Donoven and R. Hancock for
    their contribution to the development of the algorithms for maximal
    subsemigroups and smaller degree partial permutation representations.
    <P/>

    Markus Pfeiffer contributed the majority of the code relating to
    semigroups of matrices over finite fields.
    <P/>

    We would also like to acknowledge the support of the Centre of Algebra at
    the University of Lisbon, and of EPSRC grant number GR/S/56085/01.    
  </Acknowledgements>

</TitlePage>
