I am searching for a scheme $X$ which can be obtained by gluing two affine schemes (along open subsets) such that: 1) X is non-reduced; 2) $\Gamma(X,\mathcal O_X)$ is a reduced ring. Any ideas? Thanks in advance.
2026-03-30 13:40:37.1774878037
A particular example of a non-reduced scheme (with a reduced ring of global sections)?
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Hint:
Can you construct a ''fat'' projective line of some sort? Namely, remember that $\text{Spec } k[x]$ is the affine line and we get projective space by gluing together two affine lines. Can you do something similar by fattening up the lines you glue?
My example was the following. Take $\text{Proj } k[x,y,z]/z^2$. I believe that working on affines, this should produce something with only $k$ as global sections. I haven't worked it out in detail however.