- 29 Nov 2023, 17:12
- Forum: Helpdesk
- Topic: Recognizing the topology of surfaces
- Replies:
**8** - Views:
**8966**

Indeed, the question was more about the technical details; I have really only ever used the most external tools provided by Polymake - writing simple stuff like "$S_0 = new Hypersurface<Min>(DUAL_SUBDIVISION=>$my_dual_sub);" is basically the extent of my knowledge. Your answer does help me...

- 07 Nov 2023, 19:13
- Forum: Helpdesk
- Topic: Recognizing the topology of surfaces
- Replies:
**8** - Views:
**8966**

Dear Paul, Thanks for your ideas, and sorry for my slightly delayed answer (I was moving house). I understand the principles behind your suggestion, and it seems very reasonable to me, but I am still not sure how I should proceed to implement it in practice; for example, how could I get this R_C obj...

- 20 Oct 2023, 22:21
- Forum: Helpdesk
- Topic: Recognizing the topology of surfaces
- Replies:
**8** - Views:
**8966**

Dear Michael, Thanks for thinking about my problem! One thing I might not have made clear is that I don't have ONE surface whose topology I want to compute - rather, I have some process that generates thousands of surfaces whose topology I want to compute. With that in mind, I have attached the JSON...

- 20 Oct 2023, 20:24
- Forum: Helpdesk
- Topic: Recognizing the topology of surfaces
- Replies:
**8** - Views:
**8966**

Dear Paul, Thanks for your answer. As you suspected, I am more interested in surfaces in RP3, hence your second approach would not work unaltered. Regarding your first suggestion, I agree that conceptually this seems like a very sound way to proceed, but it looks like it would require me to get my h...

- 11 Oct 2023, 20:16
- Forum: Helpdesk
- Topic: Recognizing the topology of surfaces
- Replies:
**8** - Views:
**8966**

Dear all, My question is as follows. I have some patchworked surface S (in either \mathbb{R}^3 or \mathbb{R}\mathbb{P}^3 ), obtained with something like $S_0 = new Hypersurface<Min>(DUAL_SUBDIVISION=>$my_dual_sub); $S = $S_0>PATCHWORK(SIGNS=>$my_signs) I know how to compute the homology of S with co...

- 11 Aug 2022, 23:05
- Forum: Helpdesk
- Topic: Error realize()-ing a Harnack curve defined via its dual subdivision
- Replies:
**2** - Views:
**5926**

Ok, thank you very much for your clear answer and additional explanations!

Best regards,

Charles

Best regards,

Charles

- 06 Aug 2022, 23:27
- Forum: Helpdesk
- Topic: Error realize()-ing a Harnack curve defined via its dual subdivision
- Replies:
**2** - Views:
**5926**

Dear all, I tried to define a patchwork using its dual subdivision, as shown at the end of the tutorial https://polymake.org/doku.php/user_guide/tutorials/patchwork . My code is as follows : my $dual_sub = new fan::SubdivisionOfPoints(POINTS=>[[1, 2, 0, 0],[1, 1, 0, 1],[1, 0, 0, 2],[1, 1, 1, 0],[1, ...

- 21 Apr 2022, 19:17
- Forum: Helpdesk
- Topic: Is this the fastest way to compute the Betti numbers ?
- Replies:
**4** - Views:
**6801**

Great ! Thanks for the explanation.

- 21 Apr 2022, 18:41
- Forum: Helpdesk
- Topic: Is this the fastest way to compute the Betti numbers ?
- Replies:
**4** - Views:
**6801**

Thanks a lot for your answer. 1) adding "$h1->remove("PATCHWORK");" actually made a huge difference - it made my code about 5 times faster. Thank you very much, this is great ! 2) If by parameters you mean the kind of experiments I am running or the kind of computer I am using, I...

- 18 Apr 2022, 17:22
- Forum: Helpdesk
- Topic: Is this the fastest way to compute the Betti numbers ?
- Replies:
**4** - Views:
**6801**

Dear all, I have a program in which I start with a triangulation of an n-dimensional simplex - for now, the triangulation is defined using a list of monomials and a list of coefficients. I also have a (long) list of signs distributions on the vertices of that triangulation. For each signs distributi...

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