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IsTree5

checks if a facet complex is a tree

Syntax
IsTree5(L: LIST): [BOOL, LIST ]
IsTree5(L: LIST, "NOOPT"): [BOOL, LIST]
IsTree5(L: LIST, "OPT"): [BOOL, LIST]
IsTree5(L: LIST, "CS_NOOPT"): [BOOL, LIST]
IsTree5(L: LIST, "CS_OPT"): [BOOL, LIST]

Description
***** NOT YET IMPLEMENTED *****

This function is implemented in CoCoALib.

This function tests whether the facet complex described by the list L of square free power products is a tree, plus a list which:

- is empty if L is a tree

- contains three elements of a cycle of L if L is not a tree.

Four options NOOPT , OPT , CS_NOOPT , CS_OPT are available as second argument, specifying different algorithms; the default is CS_OPT .

For a full description of the algorithms we refer to the paper by M. Caboara, S. Faridi, and P. Selinger, "Simplicial cycles and the computation of simplicial trees", Journal of Symbolic Computation, vol.42/1-2, pp.77-88 (2006).

Example
  use R ::= QQ[x,y,z,t];
  D := [x*y, y*z, z*t, t*x];
  IsTree5(D);
[False, [xy, xt, yt]]
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  IsTree5([xy, yz, zt]);
[True, [ ]]
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