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Topic review - Calculating Euler characteristics
Author Message
hannes
  Post subject:  Re: Calculating Euler characteristics  Reply with quote
fix with git commit 29f72ad8f1379c65671fb9809ace7ac76fa0cd20
see https://www.singular.uni-kl.de:8002/tra ... a0cd20/git
Post Posted: Thu Oct 10, 2019 11:01 am
User56437
  Post subject:  Re: Calculating Euler characteristics  Reply with quote
So I ended up contacting the person who wrote the chern.lib library and they have corrected the code, which should be updated as well.
Post Posted: Tue Oct 01, 2019 1:03 pm
User56437
  Post subject:  Calculating Euler characteristics  Reply with quote
Hello, I am trying to use Singular to calculate Euler characteristics of some affine varieties over the complex numbers. I did a few tests using the EulerAff command and am getting strange results. For example I tried the following (and various similar alterations like changing the field to Q or R, changing the floating point number, adding more variables ...):

ring r = (complex,100,j),(x,y,z),dp;
ideal I = x;
EulerAff(I);

This gives the result 2. But this should be calculating the Euler characteristic of the complex plane and so should be 1. Does anybody know what is going on here/how I can correct this issue?
Post Posted: Wed Sep 25, 2019 12:54 pm


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