#19593 closed defect (fixed)
intervalposets in Tamari lattice should be hashable..
Reported by:  chapoton  Owned by:  

Priority:  major  Milestone:  sage6.10 
Component:  combinatorics  Keywords:  
Cc:  VivianePons  Merged in:  
Authors:  Frédéric Chapoton  Reviewers:  Travis Scrimshaw 
Report Upstream:  N/A  Work issues:  
Branch:  1ea9d4e (Commits)  Commit:  
Dependencies:  Stopgaps: 
Description
and they were.. But now:
sage: hash(TamariIntervalPosets(4)[0]) TypeError: <class 'sage.combinat.interval_posets.TamariIntervalPosets_all_with_category.element_class'> is not hashable
Change History (8)
comment:1 Changed 4 years ago by
 Branch set to public/19593
 Commit set to 58a413ae58e8a140c9f8a3bfda8aac79b775a7f7
 Status changed from new to needs_review
comment:2 Changed 4 years ago by
 Status changed from needs_review to needs_work
does not seem to work :(
comment:3 Changed 4 years ago by
In what way? I think your doctest is bad because posets are UniqueRepresentation
s, so, IIRC, the hash is the ID of the object. I think you should have a test like
sage: hash(TamariIntervalPosets(4)[0]) == hash(TamariIntervalPosets(4)[0]) True
comment:4 Changed 4 years ago by
 Commit changed from 58a413ae58e8a140c9f8a3bfda8aac79b775a7f7 to 1ea9d4e03c3e8f89115760f92fad782c8925be13
Branch pushed to git repo; I updated commit sha1. New commits:
1ea9d4e  trac #19593 better hash for tamari intervals

comment:5 Changed 4 years ago by
 Status changed from needs_work to needs_review
let us try to use another more direct way to compute the hash
comment:6 Changed 4 years ago by
 Reviewers set to Travis Scrimshaw
 Status changed from needs_review to positive_review
LGTM.
comment:7 Changed 4 years ago by
 Branch changed from public/19593 to 1ea9d4e03c3e8f89115760f92fad782c8925be13
 Resolution set to fixed
 Status changed from positive_review to closed
comment:8 Changed 4 years ago by
 Commit 1ea9d4e03c3e8f89115760f92fad782c8925be13 deleted
damned, this is not working at all, unless there is no cover relations, which is the chosen example !!!
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New commits:
trac #19593 fixing hash for Tamari intervalposets