The function depth(I,M) computes the I-depth of a ring, module, or ideal. In the most general setting, it does this by computing Ext^i(A^1/I,M) for an A-Module M, and noting where it does not vanish. If the ring in question is a polynomial ring over a field, then it merely computes the codimension of I.
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If I contains a unit, then depth(I,A) outputs infinity.
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This symbol is provided by the package Depth.m2