I'm working on a problem involving the computation of the second exterior power of certain ideals within the rings ( R1 = \mathbb{Z}[\sqrt{-5}]$R_1 = \mathbb{Z}[\sqrt{-5}]$ and R2 = \mathbb{Z}[\sqrt{5}])$R_2 = \mathbb{Z}[\sqrt{5}]$. The problem is as follows:
Let an ideal ( I = (2, 1 + \sqrt{-5}) )$I = (2, 1 + \sqrt{-5})$ as an ( R1 )$R_1$-module, I need to verify that the second exterior power ( \Lambda^2 I = 0 )$\bigwedge^2 I = 0$.
Let another ideal ( J = (2, 1 + \sqrt{5}) )$J = (2, 1 + \sqrt{5})$ as an ( R2 )$R_2$-module. However,I I need to prove that ( \Lambda^2 J \neq 0 )$\bigwedge^2 J \neq 0$.
Any insights on these computations or the underlying structure of the exterior power in this setting would be greatly appreciated.