Better printing for the genus symbol

[simonbrandhorst]

sage: G
Genus of
[ 2  0  0]
[ 0  2  0]
[ 0  0 64]
Genus symbol at 2:    [2^2]_1 :[64^1]_1

The correct symbol is

[2^2]_2:[64^1]_1 

Moreover the signature should be printed and
if the representative is very large it can be suppressed.

Depends on #25682

Component: quadratic forms

Keywords: genus

Author: Simon Brandhorst

Branch/Commit: c979627

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/25776

[simonbrandhorst]

Branch: u/sbrandhorst/bug_in_printing_of_a_genus_symbol

[simonbrandhorst]

Commit: b23a8d2

[simonbrandhorst]

New commits:

b23a8d2

print the correct oddity of a compartment

[tscrim]

comment:4

LGTM (I don't understand the math, but the code matches what you put in the comments.). Once you add the author name, you can set a positive review.

[tscrim]

Reviewer: Travis Scrimshaw

[simonbrandhorst]

Author: Simon Brandhorst

[simonbrandhorst]

comment:6

I just noticed another bug:

sage: a=matrix.diagonal([1,3])
sage: b=matrix(ZZ,2,[2,1,1,2])*2
sage: c = matrix.block_diagonal([a,b])
sage: Genus(c)
Genus of
[1 0|0 0]
[0 3|0 0]
[---+---]
[0 0|4 2]
[0 0|2 4]
Genus symbol at 2:    [1^2]_02^2 
Genus symbol at 3:     1^2 3^2

Here
Genus symbol at 2: [1^2]_0 2^2
is better.

Also it would be good to print the signature of the quadratic form and
moreover if the representative is greater than 20 x 20 or something to suppress it - just like our matrices.

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. Last 10 new commits:

b33dd62	fix coverage
d201139	Merge branch 'u/sbrandhorst/add_access_methods_to_the_genus_' of git://trac.sagemath.org/sage into t/25682/add_access_methods_to_the_genus_
3f22518	Various docfixes
d689be4	Merge branch 'develop' into t/25682/add_access_methods_to_the_genus_
851e23c	import Genus into the global namespace and small docfixed
5089a18	signature method and docfixes
9d6efa3	fix doc and revert to signature_pair_of_matrix to avoid a deprecation
5abf9ff	Raw strings for documentation.
3fc0b47	Merge commit '5abf9ffddef8b6dff940cd2c6820193959a7c870' of git://trac.sagemath.org/sage into u/sbrandhorst/25776
7af4d4a	Add Signature to the printing.

[sagetrac-git]

Changed commit from b23a8d2 to 7af4d4a

[simonbrandhorst]

Dependencies: #25682

[tscrim]

comment:11

Nitpicking: It would be a much nicer test output to run latex(G) instead of G.__latex__() (this is also a often done test). Similarly repr(s) instead of s.__repr__(). It would also be more useful to use raw strings when writing the latex strings, e.g., "\\\\" -> r"\\".

Otherwise LGTM (i.e., feel free to set a positive review if you don't want to change these things).

[sagetrac-git]

Changed commit from 7af4d4a to c979627

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

c979627

nitpicks

[simonbrandhorst]

comment:13

thank you. Those tricks were new to me.

[vbraun]

Changed branch from u/sbrandhorst/bug_in_printing_of_a_genus_symbol to c979627