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7.7.16.0. gradeNumber
Procedure from library purityfiltration.lib (see purityfiltration_lib).
- Usage:
- gradeNumber(R), R matrix, representing M=D^p/D^q(R^t) over a ring D
- Return:
- int, grade number of M
- Purpose:
- computes the grade number of M, i.e. the first i, with ext^i(M,D) !=0
returns -1 if M=0
Example:
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