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SimplicialDecomposability :: isShelling

isShelling -- determines whether a list of faces is a shelling

Synopsis

Description

Determines if a list of faces is a shelling order of the simplicial complex generated by the list.

Let S be the simplicial complex generated by the list of facets L. If S is pure, then definition III.2.1 in [St] is used. That is, L1, .., Ln is a shelling order of S if the difference in the j-th and j-1-th subcomplex has a unique minimal face, for 2 ≤j ≤n.

If S is non-pure, then definition 2.1 in [BW-1] is used. That is, L1, .., Ln is a shelling order if the intersection of the faces of the first j-1 facets with the faces of the Lj is pure and dim Lj - 1-dimensional.

i1 : R = QQ[a..e];
i2 : isShelling {a*b*c, b*c*d, c*d*e}

o2 = true
i3 : isShelling {a*b*c, c*d*e, b*c*d}

o3 = false

See also

Ways to use isShelling :