Timeline for Is every (one dimensional) n-bud of total degree n also a formal group law?
Current License: CC BY-SA 3.0
10 events
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| Oct 20, 2014 at 21:19 | comment | added | Lubin | The associator seems to be $-4x^2yz + 4xyz^2 - 2x^3yz - 7x^2y^2z + 7xy^2z^2 + 2xyz^3$ modulo degree six. | |
| Oct 20, 2014 at 16:20 | history | edited | Qiaochu Yuan | CC BY-SA 3.0 |
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| Oct 20, 2014 at 16:20 | comment | added | Qiaochu Yuan | @Baptiste: you're right, I just checked the calculation again and the correct calculation just has the $x^3$ and $y^3$ terms removed. Not sure how those got there. Thanks! | |
| Oct 20, 2014 at 13:33 | comment | added | Baptiste Calmès | A detail: your expansion modulo degree 4 terms is incorrect. The terms x^3 and y^3 cannot appear in a formal group law (since it satisfies $f(x,0)=x$ and $f(0,y)=y$). | |
| May 29, 2013 at 20:50 | comment | added | Qiaochu Yuan | Sage can symbolically manipulate multivariate polynomials (sagemath.org/doc/constructions/…) although SageMathCloud wasn't happy with the above example for some reason. | |
| May 29, 2013 at 20:26 | comment | added | Jonathan Beardsley | Also, do you happen to know of good code (I guess in Sage, which I have little experience with) for computing the homogeneous degree n terms of the associator? I'd like to show that the associator is a cocycle in a certain cohomology, but am having a difficult time writing down these rather large polynomials for anything higher than homogeneous degree 2. | |
| May 29, 2013 at 20:21 | vote | accept | Jonathan Beardsley | ||
| May 29, 2013 at 20:21 | comment | added | Jonathan Beardsley | It's interesting that what you come up with is basically the sum of symmetric functions. I guess I'll trust you that this isn't an FGL. :-) | |
| May 29, 2013 at 4:18 | history | edited | Qiaochu Yuan | CC BY-SA 3.0 |
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| May 29, 2013 at 2:33 | history | answered | Qiaochu Yuan | CC BY-SA 3.0 |