[petsc-dev] Adjacency relations in Sieve and stencils

[Chris Eldred]

I am working with a 2D unstructured mesh using sieve and I wanted to
get some advice on how to determine adjacency relations using the
topological operators provided by Sieve (cone, support, closure,
star). I have figured out the following:

Vertices for a given edge: cone(edge)
Cells for a given edge: support(edge)

Cells for a given vertex: star(vertex) \ support(vertex)
Edges for a given vertex: support(vertex)

Edges for a given cell: cone(cell)
Vertices for a given cell: closure(cell) \ cone(cell)

The set of edges associated with the cells for a given edge: U
cone(support(edge)) - ie the union of the cones of the support of the
edge

Are there other topological operators that more naturally express
these relations (especially the ones involving unions or complements)?

-- 
Chris Eldred
DOE Computational Science Graduate Fellow
Graduate Student, Atmospheric Science, Colorado State University
B.S. Applied Computational Physics, Carnegie Mellon University, 2009
chris.eldred at gmail.com