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Intersection theory: fix issue #4512 and more #4526

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4 changes: 4 additions & 0 deletions experimental/IntersectionTheory/docs/src/AbstractBundles.md
Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,10 @@ DocTestSetup = Oscar.doctestsetup()

# Abstract Bundles

## Types

The OSCAR type for abstract varieties is `AbstractBundle`.

## Constructors

```@docs
Expand Down
46 changes: 42 additions & 4 deletions experimental/IntersectionTheory/docs/src/AbstractVarieties.md
Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@ DocTestSetup = Oscar.doctestsetup()

## Types

AbsVariety <: Variety
The OSCAR type for abstract varieties is `AbstractVariety`.

## Constructors

Expand Down Expand Up @@ -60,7 +60,7 @@ degeneracy_locus(F::AbstractBundle, G::AbstractBundle, k::Int; class::Bool=false
```

!!! note
Products and blowups are described elsewhere.
Products and blow-ups are described elsewhere.

## Underlying Data of an Abstract Variety

Expand Down Expand Up @@ -161,9 +161,9 @@ product(X::AbstractVariety, Y::AbstractVariety)
```

!!! note
Blowups are described in their own section.
Blow-Ups are described in their own section.

## Integrate Chow Ring Elements
## Integrating Chow Ring Elements

```@julia
integral(x::Union{MPolyDecRingElem, MPolyQuoRingElem})
Expand All @@ -187,7 +187,45 @@ AbstractBundle of rank 2 on AbstractVariety of dim 4
julia> E = symmetric_power(Q, 3)
AbstractBundle of rank 4 on AbstractVariety of dim 4

julia> # Lines on a general cubic hypersurface in P^3:

julia> integral(top_chern_class(E))
27

```

```jldoctest
julia> T, (t, ) = polynomial_ring(QQ, [:t])
(Multivariate polynomial ring in 1 variable over QQ, QQMPolyRingElem[t])

julia> QT = fraction_field(T)
Fraction field
of multivariate polynomial ring in 1 variable over QQ

julia> P3 = abstract_projective_space(3, base = QT)
AbstractVariety of dim 3

julia> h = gens(P3)[1]
h

julia> integral(t^2*h^3+t*h)
t^2

```

```jldoctest
julia> G = abstract_grassmannian(2, 4+4)
AbstractVariety of dim 12

julia> S = tautological_bundles(G)[1]
AbstractBundle of rank 2 on AbstractVariety of dim 12

julia> E = symmetric_power(S, 2)
AbstractBundle of rank 3 on AbstractVariety of dim 12

julia> # Lines on a general complete intersection Calabi-Yau threefold of type (2,2,2,2):

julia> integral(top_chern_class(E)^4)
512

```
Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,10 @@ DocTestSetup = Oscar.doctestsetup()

# Abstract Variety Maps

## Types

The OSCAR type for abstract variety maps is `AbstractVarietyMap`.

## Constructors

```@docs
Expand Down
6 changes: 3 additions & 3 deletions experimental/IntersectionTheory/docs/src/BlowUps.md
Original file line number Diff line number Diff line change
Expand Up @@ -3,12 +3,12 @@ CurrentModule = Oscar
DocTestSetup = Oscar.doctestsetup()
```

# Blowups
# Blow-Ups

```@docs
blowup(i::AbstractVarietyMap; symbol::String = "e")
blow_up(i::AbstractVarietyMap; symbol::String = "e")
```

```@docs
blowup_points(X::AbstractVariety, n::Int; symbol::String = "e")
blow_up_points(X::AbstractVariety, n::Int; symbol::String = "e")
```
75 changes: 74 additions & 1 deletion experimental/IntersectionTheory/docs/src/BottFormulas.md
Original file line number Diff line number Diff line change
Expand Up @@ -3,5 +3,78 @@ CurrentModule = Oscar
DocTestSetup = Oscar.doctestsetup()
```

# Bott Formulas
# Bott's Formula

## Abstract Varieties With a Torus Action

### Types

The OSCAR type for abstract varieties with a torus action is `TnVariety`.

### Constructors

```@docs
tn_variety(n::Int, points::Vector{Pair{P, Int}}) where P
```

### Specialized Constructors

```@docs
tn_grassmannian(k::Int, n::Int; weights = :int)
```

```@docs
tn_flag_variety(dims::Int...; weights = :int)
```

### Underlying Data of an Abstract Variety With a Torus Action


```@docs
dim(X::TnVariety)
```

```@docs
fixed_points(X::TnVariety)
```

```@docs
tangent_bundle(X::TnVariety)
```

```@docs
tautological_bundles(X::TnVariety)
```

### Further Data Associated to an Abstract Variety With a Torus Action

`trivial_line_bundle(X::TnVariety)`
`cotangent_bundle(X::TnVariety)`
`euler_number(X::TnVariety)`

!!! note
If `X` is of type `TnVariety`, entering `total_chern_class(X)` returns the total Chern class of the tangent bundle of `X`.
Similarly for entering `chern_class(X, k)`.


## Equivariant Abstract Bundles Under a Torus Action

### Types

### Constructors

### Specialized Constructors

### Underlying Data of an Equivariant Abstract Bundle

### Further Data Associated to an Equivariant Abstract Bundle

## Integrating ...



## Example: Linear Subspaces on Hypersurfaces

```@docs
linear_subspaces_on_hypersurface(k::Int, d::Int; bott::Bool = true)
```
3 changes: 2 additions & 1 deletion experimental/IntersectionTheory/docs/src/examples.md
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ julia> integral(s1^4)
2

```

#### How Many Conics in $\mathbb P^3$ Meet Eight General Lines in $\mathbb P^3$?

```jldoctest
Expand Down Expand Up @@ -68,7 +69,7 @@ H
julia> i = map(P2, P5, [2*h])
AbstractVarietyMap from AbstractVariety of dim 2 to AbstractVariety of dim 5

julia> Bl, E, j = blowup(i)
julia> Bl, E, j = blow_up(i)
(AbstractVariety of dim 5, AbstractVariety of dim 4, AbstractVarietyMap from AbstractVariety of dim 4 to AbstractVariety of dim 5)

julia> e, HBl = gens(chow_ring(Bl))
Expand Down
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