Manchester Algebra Seminar - Carl-Fredrik Nyberg Brodda
| Dates: | 17 May 2022 |
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| Times: | 13:00 - 14:00 |
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| What is it: | Seminar |
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| Organiser: | Department of Mathematics |
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| Who is it for: | University staff, Current University students |
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Speaker: Carl-Fredrik Nyberg Brodda - Manchester
Title: The word problem for special semigroups
Abstract: The word problem for groups, first posed by M. Dehn in 1911, is one of the most important topics in combinatorial algebra. While semigroups arose as generalisations of groups, the word problem for semigroups did not arise in the analogous way: having been posed by A. Thue in 1914 with not a hint of group theory present, the word problem for semigroups would go on to see its own remarkable path towards becoming the first undecidable mathematical problem ever constructed. In this talk, I will give some background on combinatorial semigroup theory and its fascinating history, including key results by S. I. Adian and his student G. S. Makanin in the mid 1960s. I will then specialise to "special" semigroups, being semigroups whose defining relations are all of the form w=1 (in particular, all groups are special semigroups). I will present some key results and open problems. Finally, I will describe some recent advances in understanding the formal language theoretic properties of the word problem in special semigroups, solving two problems first posed by L. Zhang in 1992.
The event will also be streamed on Zoom at the usual meeting room*
- subject to equipment and connection
Tea and biscuits 12:45 in the foyer
Travel and Contact Information
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Frank Adams
Alan Turing Building
Manchester
