Opened 6 months ago
Last modified 3 months ago
#31771 new enhancement
Chart.subchart_poset, superchart_poset, Manifold.chart_poset
Reported by: | mkoeppe | Owned by: | |
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Priority: | major | Milestone: | sage-9.5 |
Component: | manifolds | Keywords: | |
Cc: | egourgoulhon, gh-mjungmath | Merged in: | |
Authors: | Reviewers: | ||
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | #31720 | Stopgaps: |
Description
Families of charts on a manifold are quasiordered by set inclusion of domains, ignoring coord_string
. Subqosets can be defined by filtering by coord_string
; an optional argument of Manifold.chart_poset
will do this.
As in #31736, the poset quotients by the equivalence relation, so its elements are finite families of charts that have the same domain.
Change History (8)
comment:1 Changed 6 months ago by
- Dependencies set to #31720
comment:2 Changed 6 months ago by
comment:3 follow-up: ↓ 7 Changed 6 months ago by
I think this quasi order is exactly what we need for presheaves.
Since the set of frames as well as of charts each constitute a presheaf, what if we wrap this up in #31703?
Besides, what do you mean with "Subqosets"?
comment:4 Changed 6 months ago by
qoset = quasi-ordered set
comment:5 Changed 6 months ago by
But when we take coord_string
into account again, shouldn't this become a poset? So you mean subqosets that are actual posets, right?
comment:6 Changed 6 months ago by
Two subsets with a different name can turn out to be equal. If two restrictions of a chart are defined on these two subsets, then I think these will be distinct but equal elements of the qoset as well.
comment:7 in reply to: ↑ 3 Changed 6 months ago by
Replying to gh-mjungmath:
Since the set of frames as well as of charts each constitute a presheaf, what if we wrap this up in #31703?
Sure, that would work; perhaps you can expand that ticket's description a bit.
comment:8 Changed 3 months ago by
- Milestone changed from sage-9.4 to sage-9.5
Probably perfect substitute for the current
display
implementation of scalar fields.