#12090: Arrangements of pseudolines
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Reporter: ncohen | Owner: mhampton
Type: enhancement | Status: needs_info
Priority: major | Milestone: sage-5.10
Component: geometry | Resolution:
Keywords: | Work issues: needs rebase
Report Upstream: N/A | Reviewers:
Authors: Nathann Cohen | Merged in:
Dependencies: #12159 #11634 | Stopgaps:
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Comment (by hthomas):
Bonjouuuuuuur!
Yes, I was looking to see what old combinatorial patches were lying around
bitrotting. This deserves a better fate!
I didn't change the actual Felsner encoding. All I did was the following,
in the procedure for turning a Felsner encoding into an arrangement.
After you've pulled off a zero and a one, you have to update i. If
seq[i-1] is non-empty, you decrement i. Fine. Otherwise, you either left
i as it was, or incremented it, based on whether seq[i] was non-empty.
But I think that at this point you can always increment it: the next thing
you're going to pull off is not going to be in position i, because that
would have to be the same crossing as the one you just removed. Am I
wrong?
I agree, the braid group strands are pretty; it would be good to reuse
them.
I don't know if this is worth bothering about, but for someone who is
learning about the Felsner encoding, it might be convenient to be able to
see the braid displayed with the crossings in the sequence that they're
read off the Felsner diagram.
Do you know what is bothering the patchbot? The doctest_continuation
plugin is known to be broken (fixed, apparently, in the newest version of
the patchbot), but it's also failing to build the documentation, though it
hardly seems likely that this is our problem.
che(eeee)ers,
Hugh
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12090#comment:12>
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