#19661: the srgs from Cossidente and Penttila construction of hemisystems in
H(3,q^2)
-------------------------+-------------------------------------------------
Reporter: | Owner:
dimpase | Status: needs_review
Type: | Milestone: sage-7.0
enhancement | Resolution:
Priority: major | Merged in:
Component: graph | Reviewers:
theory | Work issues:
Keywords: | Commit:
Authors: | 16f1f711fce54ae770c81dd957e5cad2baea8fe1
Report Upstream: N/A | Stopgaps:
Branch: |
public/19661 |
Dependencies: |
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Comment (by dimpase):
Come on, why do you think that 10 lines of `libgap.blah(libgap.foo...)`,
e.g. in ` _polar_graph()` in the same file are better than an honest
10-line GAP function? Is the following a beacon of beauty in your eyes:
{{{
W=libgap.FullRowSpace(libgap.GF(q), m) # F_q^m
B=libgap.Elements(libgap.Basis(W)) # the standard basis of W
V = libgap.Orbit(g,B[0],libgap.OnLines) # orbit on isotropic points
gp = libgap.Action(g,V,libgap.OnLines) # make a permutation group
s = libgap.Subspace(W,[B[i] for i in range(m//2)]) # a totally
isotropic subspace
# and the points there
sp = [libgap.Elements(libgap.Basis(x))[0] for x in
libgap.Elements(s.Subspaces(1))]
h = libgap.Set(map(lambda x: libgap.Position(V, x), sp)) # indices of
the points in s
L = libgap.Orbit(gp, h, libgap.OnSets) # orbit on these subspaces
}}}
Is it contrary to your religion, or something? I just don't get it, sorry.
--
Ticket URL: <http://trac.sagemath.org/ticket/19661#comment:30>
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