Struct SegreClass 

pub struct SegreClass {
    pub coefficients: BTreeMap<Partition, i64>,
    pub grassmannian: (usize, usize),
}

Segre class: the formal inverse of the total Chern class.

If c(E) = 1 + c_1 + c_2 + … is the total Chern class, then s(E) = c(E)^{-1} = 1 - c_1 + (c_1^2 - c_2) - …

Fields

coefficients: BTreeMap<Partition, i64>

Expansion in the Schubert basis

grassmannian: (usize, usize)

Grassmannian parameters

Implementations

impl SegreClass

pub fn from_chern(csm: &CSMClass) -> Self

Compute Segre class from a CSM (Chern) class by formal inversion.

s = c^{-1} in the ring of Schubert classes.

Contract

ensures: s · c == identity (in the Schubert ring, up to truncation)

pub fn excess_intersection(&self, excess_dim: usize) -> i64

Compute excess intersection number using Segre class.

When the intersection is not transverse (excess dimension > 0), the corrected intersection number is:

corrected = ∫ s_excess(N) ∩ [X ∩ Y]

Contract

ensures: result == sum of Segre coefficients at codimension excess_dim

Trait Implementations

impl Clone for SegreClass

fn clone(&self) -> SegreClass

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SegreClass

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for SegreClass

fn eq(&self, other: &SegreClass) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for SegreClass

impl StructuralPartialEq for SegreClass