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7.7.16.0. projectiveDimension
Procedure from library purityfiltration.lib (see purityfiltration_lib).

Usage:
projectiveDimension(R,i,j), R matrix representing the Modul M=coker(R)
int i, with i=0 or i=1, j a natural number

Return:
list T, a projective resolution of M and its projective dimension

Purpose:
if i=0 (and by default), T[1] gives a shortest left resolution of M=D^p/D^q(R^t) and T[2] the left projective dimension of M
if i=1, T[1] gives a shortest right resolution of M=D^p/RD^q and T[2] the right projective dimension of M
in both cases T[1][j] is the (j-1)-th syzygy module of M

Note:
The algorithm is due to A. Quadrat, D. Robertz, Computation of bases of free modules over the Weyl algebras, J.Symb.Comp. 42, 2007.

Example:
 


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