Timeline for Generalized free product of semigroups with amalgamated subsemigroups
Current License: CC BY-SA 3.0
17 events
| when toggle format | what | by | license | comment | |
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| Aug 1, 2013 at 16:50 | vote | accept | Boris Novikov | ||
| Aug 1, 2013 at 16:44 | answer | added | Misha | timeline score: 2 | |
| Jul 29, 2013 at 16:57 | comment | added | Boris Novikov | @Misha: Thank you very much. I think for me now it is enough. Would you like to transform this remark into an answer? | |
| Jul 29, 2013 at 4:13 | comment | added | Misha | If I understand it correctly, what Hanna Neumann defined is not a special case graph of groups, but of what is now called a "complex of groups". Search for "complex of semigroups" returned nothing. My guess then is that you are on your own. My suggestion is to look for a CAT(0)-concept which might work in this context and would yield a "developable complex" of semigroups and guarantee, say, that vertex semigroups are embedded. Reading first Gersten and Stallings (for triangles of groups) and then Bridson and Haefliger (in general) might be a good start. | |
| Jul 28, 2013 at 15:14 | answer | added | user6976 | timeline score: 1 | |
| Jul 27, 2013 at 17:01 | answer | added | Anton Klyachko | timeline score: 0 | |
| Jul 27, 2013 at 16:09 | comment | added | Boris Novikov | @ Mark Sapir: Mark, all of these references deal with the case when there is only one amalgamated subsemigroup -- the intersection of all semigroups. I need the case when we have a family of amalgamated subsemigroups -- the intersections of pairs of semigroups. | |
| Jul 27, 2013 at 16:00 | comment | added | user6976 | @Boris: What do you want to know and cannot find from the 162 references given by googling "amalgam of semigroups"? | |
| Jul 27, 2013 at 15:42 | comment | added | Boris Novikov | @Misha: Misha, spasibo. This information is useful for me also. | |
| Jul 27, 2013 at 15:08 | comment | added | Misha | @BorisNovikov: Boris, I know nothing about semigroups, but for groups, $\pi_1$ of a finite graph of groups can be always reduced to an iterated amalgam/HNN extension where on each step only one subgroup is involved. For countable graphs one can use this + direct limit. | |
| Jul 27, 2013 at 14:28 | comment | added | Boris Novikov | @ Benjamin Steinberg: Benjamin, thank you, but I am interested just in the case of several subsemigroups. | |
| Jul 27, 2013 at 14:14 | comment | added | Benjamin Steinberg | Yes people have although most of the attention has been focused on one subsemigroup. | |
| Jul 27, 2013 at 13:43 | history | edited | Boris Novikov | CC BY-SA 3.0 |
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| Jul 27, 2013 at 8:45 | history | edited | Boris Novikov |
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| Jul 27, 2013 at 8:39 | history | edited | Boris Novikov | CC BY-SA 3.0 |
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| Jul 27, 2013 at 8:35 | history | edited | Ricardo Andrade |
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| Jul 27, 2013 at 7:32 | history | asked | Boris Novikov | CC BY-SA 3.0 |