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Sep 25, 2014 at 2:42 history edited Alexandre Eremenko CC BY-SA 3.0
added 2 characters in body
Jun 27, 2014 at 19:43 comment added Joseph O'Rourke @BenjaminSteinberg: Yes, the definition of fundamental polygon is that each symbol should appear exactly twice. I will make that explicit. Thanks!
Jun 27, 2014 at 17:31 comment added Benjamin Steinberg To get a surface each letter should appear exactly twice. Maybe this was implicit in the question.
Jun 27, 2014 at 14:20 comment added Benjamin Steinberg I am confused. There are one-relator groups with even length relations that are not surface groups. The string $ab^6a^{-1}b^{-8}$ defines a non-Hopfian Baumslag-Solitar group and hence is not a surface group.
Jun 27, 2014 at 13:19 history edited Alexandre Eremenko CC BY-SA 3.0
added 128 characters in body
Jun 27, 2014 at 13:10 comment added David E Speyer Also, you need to do orientable and unorientable surfaces separately.
Jun 27, 2014 at 13:09 comment added Alexandre Eremenko Arnaud, thanks for your correction.
Jun 27, 2014 at 13:08 history edited Alexandre Eremenko CC BY-SA 3.0
added 1 character in body
Jun 27, 2014 at 12:58 comment added Arnaud Isn't this a proof that the answer to 2. is Yes, i.e. that combinatorially distinct strings can correspond to the same surface ?
Jun 27, 2014 at 12:53 history edited Alexandre Eremenko CC BY-SA 3.0
added 215 characters in body
Jun 27, 2014 at 12:47 vote accept Joseph O'Rourke
Jun 27, 2014 at 12:46 history answered Alexandre Eremenko CC BY-SA 3.0