ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Wed, 27 Feb 2019 04:36:56 +0100Calculating Milnor Numbers of Polynomials Using Singular via Sagehttps://ask.sagemath.org/question/45557/calculating-milnor-numbers-of-polynomials-using-singular-via-sage/I'm using Singular via Sage Math to calculate the Milnor numbers of a large number of polynomials. For most polynomials, doing `polynomial.milnor()` works fine, however I am getting a `-1` when I have a variable raised to a power times another variable. I have manually calculated the first Milnor number, and it should be `8`. For instance:
Works fine:
sage: ring = singular.ring(0,'(x,y,z)','ds')
sage: polynomial = singular('-x2+x3-y3+xy3-z5+xz5')
sage: _=singular.lib('sing.lib')
sage: polynomial.milnor()
8
Returns error:
sage: polynomial2 = singular('y2-x3-z2x2')
sage: polynomial2.milnor()
-1
I am following these documentation pages:
- Interface to Singular (Sage Interpreter Interfaces)
- D.6.15.10 milnor (Singular Documentation)
I can't publish links due to low karma, sorry!
By the second page, the `-1` would imply that the function is an isolated complete intersection singularity. This function does not have an ICIS to my knowledge, and I have tested several other functions which I can provide. I think that singular is interpreting the polynomial as `y2-x3-z^(2x2)`, instead of the wanted `y2-x3-(z2)(x2)`, but I am new to Sage and unsure of how to fix this (I attempted parentheses and it threw back an error).StrongPiccoloWed, 27 Feb 2019 04:36:56 +0100https://ask.sagemath.org/question/45557/