TITLE: Are there analogous statements for the number of zeros of a section in terms of the Euler class, even when the relevant spaces are not manifolds?  
QUESTION [8 upvotes]: Let $V \rightarrow M$ be an oriented rank $k$ vector bundle over a compact orientd manifold $M$. Let $X \subset M$ be a 
compact topological subspace of $M$ that is a smooth oriented submanifold of 
dimension $k$, except possibly at a a set of points that have 
``dimension'' less than or equal to $k-2$.  More precisely, the set of singular points is contained inside a 
submanifold of dimension $k-2$ or less. 
Let 
$s :X \rightarrow V$ be 
the restriction of a smooth section from $M$ to $V$. 
Assume that when restricted to $X$, the section vanishes only on the smooth points of $X$, 
and it vanishes transversally. Is it true that the number of zeros 
of $s$ inside $X$, counted with a sign is the Euler class of $V$ evaluated on the fundamental class of 
$X$ , ie 
$$ +-|s^{-1}(0)| = \int_{[X]} e(V)  $$ 
We need $X$ to have singularities of dimension $k-2$ or less, to 
ensure that it defines a homology class $[X]$ (ie to make sure 
that the integration actually makes sense). Note that $[X]$ is 
an element of $H_k(M, \mathbb{Z})$  and $e(V) \in H^k(M, \mathbb{Z})$. 
So the expression makes perfect sense, even though $X$ is a singular space. 
I believe this statement is true, but is there a reference for this 
fact?

REPLY [3 votes]: You make several assumptions, one being that $X$ is a stratified space, carrying an orientation class.  The answer to you question is yes,  under more restrictive assumptions.   Here they are.

The  section $s$ vanishes transversally along $M$.
The zero set  $s^{-1}(0)$ intersects the stratified space $X$ transversally. 

The complete rigorous proof  is a bit more involved, and  the clearest argument I know  is sheaf theoretic, and it involves a sheaf theoretic  version of the Poincare duality, also known as  Verdier duality.  All  the information you need you can find in B. Iversen's book Cohomology of Sheaves, especially chapters IX and X.
Addendum I realize  you do not need these stringent    conditions.      Denote by $V_X$ the restriction of $V$ to $X$ and by $\tau_X$ its  Thom class viewed as a class in the local cohomology of $V_X$ along $X$, $\tau_X\in H^k_X(V_X)$ (integer coefficients). We can then arrange that $\tau_X$ has support in a tiny neighborhood  of $X$ in $V_X$. Then $e(V_X)=s^*\tau_X\in H^k(X)$ is supported in a tiny open  neighborhood $N$ of $s^{-1}(0)\cap X$ in $X$, i.e., $e(V_X)$ is in the image of $H^k(X, X\setminus N)$ in $H^k(X)$.  Now use the technology in Iversen to conclude that 
$$ \langle e(V_X), [X]\rangle  =\sum_{s(x)=0} \epsilon(x), $$
where $\epsilon(x)\in\{\pm 1\}$ is the local Euler number of $S$ at $x$, and $\langle-,-\rangle $ denotes the pairing between  cohomology and homology.   (This is a bit long.)