#19197: LatticePoset: add breadth()
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       Reporter:  jmantysalo         |        Owner:
           Type:  enhancement        |       Status:  positive_review
       Priority:  major              |    Milestone:  sage-6.9
      Component:  combinatorics      |   Resolution:
       Keywords:                     |    Merged in:
        Authors:  Jori Mäntysalo     |    Reviewers:  Nathann Cohen
Report Upstream:  N/A                |  Work issues:
         Branch:                     |       Commit:
  u/jmantysalo/latticeposet__add_breadth__|  
9c05f49e95504acc1a37ea942764886c53f57198
   Dependencies:                     |     Stopgaps:
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Comment (by jmantysalo):

 Replying to [comment:30 ncohen]:
 > By the way: it seems to me that, theoretically speaking, having breadth
 `>=b` is equivalent to:
 >
 > {{{
 > sage: G1 = my_lattice.hasse_diagram().transitive_closure()
 > sage: G2 = posets.BooleanLattice(p).hasse_diagram().transitive_closure()
 > sage: G1.subgraph_search(G2,induced=True)
 > True
 > }}}

 And that is same as `L.has_isomorphic_subposet(Posets.BooleanLattice(b))`.
 I guess you are right. (But not sure - must think about this.)

 I made an example of smallest lattice with breadth 4 with
 `completion_by_cuts()` and did not notice that the result was just
 `BooleanLattice(4)`. Oops.

 And that means that my example of lattice with breadth 4 is stupid, as it
 hides the structure to dig6 string.

--
Ticket URL: <http://trac.sagemath.org/ticket/19197#comment:31>
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