Processing math: 100%

The Stacks project

Lemma 76.44.9. Let S be a scheme. Let i : Z \to Y and j : Y \to X be immersions of algebraic spaces over S. Assume that the sequence

0 \to i^*\mathcal{C}_{Y/X} \to \mathcal{C}_{Z/X} \to \mathcal{C}_{Z/Y} \to 0

of Lemma 76.5.6 is exact and locally split.

  1. If j \circ i is a quasi-regular immersion, so is i.

  2. If j \circ i is a H_1-regular immersion, so is i.

  3. If both j and j \circ i are Koszul-regular immersions, so is i.

Proof. Immediate from the case of schemes, see Divisors, Lemma 31.21.8. \square


Comments (0)


Your email address will not be published. Required fields are marked.

In your comment you can use Markdown and LaTeX style mathematics (enclose it like $\pi$). A preview option is available if you wish to see how it works out (just click on the eye in the toolbar).

Unfortunately JavaScript is disabled in your browser, so the comment preview function will not work.

All contributions are licensed under the GNU Free Documentation License.