YORK SEMIGROUP

Summer 2009/10

  • Inverse semigroups and inductive groupoids Victoria Gould, 4th May 2010
  • Semigroups of left I-quotients Nassraddin Ghroda, 11th May 2010
  • Symmetric and dual symmetric inverse monoids James East, 20th May 2010
  • Applications of order-preserving partial permutations James East, 21st May 2010
  • Beyond the Ehresmann-Schein-Nambooripad Theorem Christopher Hollings, 25th May 2010
  • Ordered covers Lubna Shaheen, 1st June 2010
  • Structure theorems for weakly B-abundant semigroups Yanhui Wang, 8th June 2010
  • An Introduction to Graph Expansions Claire Cornock, 15th June 2010

    Autumn 2010/11

  • Short presentations by Victoria Gould, Claire Cornock and Lubna Shaheen on: `A note on maximal subgroups of free idempotent generated subsemigroups over bands' by Igor Dolinka arXiv:1010.3737; `Free adequate semigroups' by Mark Kambites arXiv:0902.0927; `Clifford semigroups such that SF is axiomatisable' by Lubna Shaheen, 1st November 2010
  • `The Morita theory of semigroups and applications' Mark Lawson, 8th November 2010
  • Short presentations by Victoria Gould, Lubna Shaheen and Yanhui Wang on: `Numerical Semigroups' by J.C. Rosales and P.A. Garcia-Sanchez, book review by Ralf Froberg, Semigroup Forum 81 (2010), 555-557; `The semigroup generated by certain operators on the congruence lattice of a Clifford semigroup' by M. Petrich, Semigroup Forum 45 (1992), 332-341; `Groupoids and Cayley graphs' by Brian Leary, 15th November 2010
  • `A common framework for restriction semigroups and regular *-semigroups' Peter Jones, 22nd November 2010
  • `The finite F-inverse cover problem' Maria Szendrei, 29th November 2010
  • `Equations defining the polynomial closure of lattice of languages', Mario Branco, 6th December 2010.
  • `Equations defining the polynomial closure of lattice of languages II', Mario Branco, 6th December 2010.

    `Spring' 2010/11

  • Presentation by Victoria Gould on The Knuth-Bendix algorithm and the conjugacy problem in monoids by Fabienne Chouraqui, 9th February 2011
  • `A short history of inverse semigroups' Christopher Hollings (Oxford), 16th February 2011
  • `An introduction to model theory of S-acts and S-posets' Lubna Shaheen, 23rd February 2011
  • Varieties of restriction semigroups Claire Cornock, 2nd March 2011
  • The Thompson group V John Fountain, 9th March 2011
  • Monoids acting by isometric embeddings Mark Kambites (Manchester), 16th March 2011

    `Summer' 2010/11

  • Inverse semigroups acting on graphs and trees Jim Renshaw (Southampton), 12th May 2011
  • Statement calculus; Victoria Gould (York), 18th May 2011
  • Beyond orthodox semigroups, Yanhui Wang (York), 25th May 2011
  • Statement calculus II; Victoria Gould (York), 1st June 2011
  • First order languages and structures; Victoria Gould (York), 8th June 2011
  • Maximal subsemigroups of the semigroup of mappings on an infinite set, James Mitchell (St Andrews), 15th June 2011.
  • Cohomological dimension of inverse semigroups, Nick Gilbert (Heriot-Watt), 22nd June 2011.

    Autumn 2011/12

  • Non-commutative Stone duality, Mark Lawson (Heriot-Watt), October 19th 2011.
  • Ends of Semigroups, Simon Craik (St Andrews), 2nd November 2011.
  • Weakly U-abundant semigroups, Yanhui Wang, 9th November 2011.
  • Restriction and related semigroups, Victoria Gould, 16th November 2011.
  • The kernel of a monoid morphism, Jean-Eric Pin, 24th November 2011.
  • An Introduction to Zappa-Szep Products, Rida-e-Zenab, 7th December 2011.
  • Synchronizing groups and semigroups, Peter Neumann, 14th December 2011.
  • Locally Ehresmann semigroups, Dandan Yang, 21st December 2011.
  • Restriction and related semigroups cont. Victoria Gould, 21st December 2011.

    Spring 2011/12

  • Free idempotent generated semigroups, Dandan Yang, 11th January 2012.
  • Covers of acts over monoids, Alex Bailey (Southampton) 18th January 2012.
  • Independence Algebras, Victoria Gould 25th January 2012.
  • E-unitary and almost factorisable orthodox semigroups, Miklos Hartmann 2nd February 2012.
  • Free idempotent generated semigroups II , Dandan Yang, 9th February 2012.
  • Embeddable E-unitary orthodox semigroups, Miklos Hartmann 15th February 2012.
  • Strongly T-proper left Ehresmann monoids Yanhui Wang, 22nd February 2012.
  • Idempotent tropical matrices Marianne Johnson, 29th February 2012.
  • Burrows-Wheeler transforms and de Bruijn Words, Peter Higgins, 7th March 2012.
  • Short presentations by Victoria Gould, Dandan Yang and Rida Zenab on: `Inverse semigroup expansions and their actions on C^*-algebras' by Alcides Buss and Ruy Exel arXiv:1112.0771v1; `On a problem of M. Kambites regarding abundant semigroups' by Joao Araujo and Michael Kinyon arXiv:1006.3677 and `Malcev products of unipotent monoids and varieties of bands', by Mario Petrich, Semigroup Forum 83 161-189 (2011), 14th March 2012.

    Summer i.e. the rainy season 2011/12

  • Short presentations by Miklos Hartmann and Yanhui Wang, 25th April 2012
  • Free idempotent generated semigroups over biordered sets Dandan Yang, 2nd May 2012
  • Zappa-Szep products of groups and semigroups Rida Zenab, 9th May 2012
  • Free idempotent generated semigroups over the full linear monoid Bob Gray (Lisbon) 16th May 2012
  • `Semigroup nearrings', John Meldrum (Edinburgh), 13th June 2012.