parameterTestIdeal(R)
This function computes the parameter test ideal of a Cohen-Macaulay ring $R$. Technically, it computes \tau($\omega$) : $\omega$ where $\omega$ is a canonical module of $R$, and \tau($\omega$) is the (parameter) test module, as computed by testModule. For example, the ring $R$ in the following example is $F$-rational, and so its parameter test ideal is the unit ideal.
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Consider now a non-$F$-rational Gorenstein ring, whose test ideal and parameter test ideal coincide.
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The object parameterTestIdeal is a method function with options.