Intersection matrix (desingularization of surfaces) (#4050)

* add intersection matrix for desingularization of surfaces --------- Co-authored-by: anne <anne@krueger-berg.de> Co-authored-by: Tommy Hofmann <thofma@gmail.com>
oscar-system · Sep 17, 2024 · 6d184a7 · 6d184a7
1 parent d40e972
commit 6d184a7
Show file tree

Hide file tree

Showing 6 changed files with 802 additions and 63 deletions.
diff --git a/experimental/IntersectionTheory/src/IntersectionTheory.jl b/experimental/IntersectionTheory/src/IntersectionTheory.jl
@@ -6,8 +6,9 @@ import ..Oscar: AffAlgHom, Ring, MPolyDecRingElem, symmetric_power, exterior_pow
 import ..Oscar: basis, betti, chow_ring, codomain, degree, det, dim, domain, dual, gens, hilbert_polynomial, hom, integral, rank, signature, partitions
 import ..Oscar.AbstractAlgebra: combinations
 import ..Oscar.AbstractAlgebra.Generic: FunctionalMap
-import..Oscar: pullback, pushforward, base, OO, product, compose
+import ..Oscar: pullback, pushforward, base, OO, product, compose
 import ..Oscar: trivial_line_bundle
+import ..Oscar: intersection_matrix
 import ..Oscar: chern_class
 
 export a_hat_genus
@@ -41,7 +42,6 @@ export euler
 export euler_pairing
 export graph
 export hyperplane_class
-export intersection_matrix
 export l_genus
 export linear_subspaces_on_hypersurface
 export line_bundle

diff --git a/experimental/Schemes/src/BlowupMorphism.jl b/experimental/Schemes/src/BlowupMorphism.jl
@@ -864,6 +864,7 @@ end
                                                  #     if is_embedded == false
   resolves_sing::Bool                            # domain(maps[end]) smooth?
   is_trivial::Bool                               # codomain already smooth?
+  is_strong::Bool                                # snc divisors ensured?
   transform_type::Symbol                         # can be :strict, :weak or :control
                                                  #     only relevant for is_embedded == true
 
@@ -875,6 +876,11 @@ end
                                                  # total transform, not set for is_embedded == false
                                                  # or transform_type == strict
   controlled_transform::AbsIdealSheaf            # holds weak or controlled transform according to transform_type
+  dont_meet::Vector{Tuple{Int,Int}}              # mostly for dim=2: intersections which cannot exist according
+                                                 # to intermediate computations
+  caution_multi_charts::Vector{Tuple{Int,Int}}   # only for dim=2: intersection of divisors not
+                                                 # entirely visible in a single chart
+
 
   # fields for caching to be filled a posteriori (on demand, only if partial_res==false)
   underlying_morphism::CompositeCoveredSchemeMorphism{DomainType, CodomainType}