If $f:X\to S$ is a universal homomorphism, is $f':X\times_S X\to X$ always a nil-immersion? This seems to be easy, yet possibly I miss something. Should I give references to this fact in a paper?
If $f:X\to S$ is a universal homomorphism, is $f':X\times_S X\to X$ a nil-immersion?
Mikhail Bondarko
- 16.9k
- 4
- 34
- 98