Algebraic stacks and open source algebraic geometry
We re having problems with bots hammering the site. For example since this morning we ve got 65 thousand requests for bibliography items (and it isn t noon yet). As we have only 700 bibliography entries, this means there are more than 90 Continue reading
OK, I went through all of the comments and we have a brand new version of the Stacks project. Enjoy!
This is just a quick note so if people google this issue they see that one needs to be careful (I think there are some positive things in the literature in special situations). Let k be a field. Let R Continue reading
I wanted to just present an explicit example of a nonvanishing higher de Rham cohomology group of the spectrum of an Artinian finite dimensional C-algebra. Consider an element f of C[x, y] where C is the complex numbers. Let Continue reading
Recording 2 examples here. The first is to consider for n > 1 the map A^n > P^n, (x_1, , x_n) maps to (x_1x_2 x_n : x_1 1 : : x_n 1) This map is quasi-finite and flat, Continue reading
Let A be a ring and let I be an ideal of A. Let (X, O_X) be a space with a sheaf of A-algebras (or X could be a site). Let F be a sheaf of O_X-modules. Set F_n = Continue reading
OK, I went through all of the comments and we have a brand new version of the Stacks project. The last time we did this was on June 6, 2024. We now have more than 650 contributors. Enjoy!
Let X be an affine variety over a field k of characteristic 0. Then we have the algebraic de Rham complex Omega* of X over k. The algebraic de Rham cohomology H^*_{dR}(X/k) of X over k is then the cohomology Continue reading
OK, I went through all of the comments and we have a brand new version of the Stacks project. The last time we did this was on March 3, 2023. We now have more than 600 contributors. Enjoy!
This is to advertise a 2 year research post-doc position with me here in the math dept at Columbia University. We have a very active and strong department and you will get to work with me (I hope that is Continue reading