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boundaryCells -- returns the boundary cells of the given cell

Synopsis

Description

Given a cell C, this command returns a list whose elements are the boundary cells of C. This differs from boundary in that it returns only the boundary cells of C, whereas boundaryCells returns a list of two-element sequences of the boundary cells and their corresponding orientation.

i1 : R = QQ[x,y,z];
i2 : vx = newSimplexCell({},x);
i3 : vy = newSimplexCell({},y);
i4 : vz = newSimplexCell({},z);
i5 : exy = newSimplexCell {vx,vy};
i6 : C = cellComplex(R,{exy,vz});
i7 : boundaryCells(exy)

o7 = {Cell of dimension 0 with label x, Cell of dimension 0 with label y}

o7 : List
i8 : boundaryCells(vz)

o8 = {}

o8 : List
i9 : R = QQ;
i10 : P = convexHull matrix {{1,1,-1,-1},{1,-1,1,-1}};
i11 : C = cellComplex(R,P);
i12 : f = (cells(2,C))#0;
i13 : boundaryCells(f)

o13 = {Cell of dimension 1 with label 1, Cell of dimension 1 with label 1,
      -----------------------------------------------------------------------
      Cell of dimension 1 with label 1, Cell of dimension 1 with label 1}

o13 : List

See also

Ways to use boundaryCells :

For the programmer

The object boundaryCells is a method function.