4
votes
1answer
177 views
Axiomatic intersection theory
Is there an axiomatic intersection theory?
What I expect is something like:
An intersection theory is a functor from the category of schemes(or other spaces) to the category of al …
2
votes
0answers
129 views
Bezout’s theorem for non-proper intersections?
Is there a version of Bézout's theorem for non-proper intersections?
For my specific problem, the setup is as follows: Let $P_1,P_2,P_3,P_4\in\mathbb{C}[z_1,z_2,z_3,z_4]$, and su …
3
votes
0answers
74 views
Reference request: Samuel’s multiplicity and degree
I am looking for references for the following simple facts.
Let $Y\subset \mathbb{P}^n$ be a variety (or pure-dimensional algebraic set). For $P\in Y$ denote by $e_p(Y)$ the (Sam …
3
votes
0answers
43 views
Divisibility of all entries in an intersection form
What are situations where one can conclude that all entries of an intersection form are divisible by an integer?
More precisely: $F \subset S$ is a proper connected (usually red …
0
votes
0answers
74 views
Relation between the index of (the sum of) lattices in euclidean space, and their orthogonal complement.
I am trying to figure out something concerning the index of lattices.
The question came about after reading the paper of W.Fulton and B.Sturmfels, ("Intersection theorey on toric …
1
vote
0answers
79 views
Non-proper intersection of projective schemes
Let $X, Y$ be projective varieties in $\mathbb{P}^n$ for $n>10$. Assume that dimensions of $X,Y$ are greater than $n/2$. My first question is as follows:
Is there a …
1
vote
1answer
213 views
euler class of the normal bundle and self intersection number
Let $S$ be a compact submanifold of $X$ smooth manifold. I know that $T_X|_S=T_S\oplus N_{S/X}$ where $N_{S/X}$ is the normal bundle. I have read that the euler class $e(N_{S/X})$ …
3
votes
1answer
190 views
Local model of virtual fundamental cycle
The following baby version of virtual fundamental cycle is well known:
Let $M\subset V$ be the zero locus of a section $s$ of a vector bandle $E \to V$, in general $s$ is not tran …
6
votes
2answers
356 views
Top chern class under finite, unramified, dominant morphism
Situation: Let $\Bbbk$ be an algebraically closed field. Assume that $\pi:Y\to X$ is an finite, dominant, unramified morphism between nonsingular varieties of dimensions $n$. Let $ …
7
votes
1answer
239 views
Commutativity of the Chow ring in positive characteristic
I was looking in Ravi Vakil's notes on Intersection Theory, Class 20, where he introduces the bivariant intersection theory, in particular the Chow ring $A^\ast (X)$.
On p. 2, he …
6
votes
0answers
148 views
Flat morphisms whose fibers are affine spaces
Let $f:X \to Y$ be a flat morphism, such that each fiber is isomorphic to the affine space $\mathbb{A}^n$. Then is is true that $f$ is a Zariski affine bundle? If not, is it at lea …
1
vote
1answer
163 views
Lefschetz Fixpoint theorem for non-orientable manifolds
The classical lefschetz fixpoint theorem is stated for oriented compact manifolds $M$ and a smooth map $f:M\to M$ as follows:
the intersection number $I(\Delta, \mathrm{graph}(f))$ …
3
votes
1answer
393 views
Self-intersection and the normal bundle
Let $X/k$ be a surface nonsingular and proper over an algebraically closed field $k$. Let $C \subset X$ be a nonsingular curve. Then it is clear that the self-intersection $(C \cdo …
3
votes
3answers
434 views
Cohomology of vector bundles via Intersection Theory
Let $X$ be a smooth projective variety over a fixed field $k$ (take $k = \mathbb{C}$ if necessary). For a vector bundle $E$ on $X$, $ch(E)$ will be in the Chow ring.
$\textbf{Ques …
8
votes
1answer
312 views
Schemes with no nonconstant maps to lower dimensional schemes
Fix an algebraically closed field $k$ (arbitrary characteristic), all schemes will be of finite type over $k$.
(Property *): I'm interested in (classes of) examples of schemes $X$ …

