Compute Ext with Macaulay2

Question

I want to compute Ext with Macaulay2.

I see in the website they write how to do it, but I can not do it. Can anyone help me with an example?

For example, let $S=k[x,y,z,t]$. How to compute $\mathrm{Ext}^i_S (S/(xy^2,x^2z),S)$ for some $i$? How to interpret it?

Thanks.

Answer 1

S = QQ[x,y,z,t]

M = module S/ideal "xy2,x2z"

for i from 0 to 4 list Ext^i (M,S)

In general, if you have installed M2 property, viewHelp would direct you to a help page, and help would give you a short help message in M2.