Wrap saturation2 and use it for Laurent polynomials (oscar-system#2562)

JohnAAbbott · Jul 14, 2023 · 19a211e · 19a211e
1 parent 3b64d46
commit 19a211e
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diff --git a/experimental/Laurent/src/Laurent.jl b/experimental/Laurent/src/Laurent.jl
@@ -160,7 +160,7 @@ function preimage(f::MPolyAnyMap{X, <: LaurentMPolyRing, Y, Z}, I::LaurentMPolyI
                          # the Laurent polynomial ring R
     _R = base_ring(II)
     for g in gens(_R)
-      II = saturation(II, g*_R)
+      II = Oscar._saturation2(II, g*_R)
     end
     # We need to translate to an ideal of R
     return ideal(R, map(x -> map_coefficients(identity, x, parent = R), gens(II)))

diff --git a/src/Rings/mpoly-ideals.jl b/src/Rings/mpoly-ideals.jl
@@ -276,6 +276,16 @@ function saturation(I::MPolyIdeal{T}, J::MPolyIdeal{T}) where T
   K, _ = Singular.saturation(I.gens.S, J.gens.S)
   return MPolyIdeal(base_ring(I), K)
 end
+
+# the following is corresponding to saturation2 from Singular
+# TODO: think about how to use use this properly/automatically
+function _saturation2(I::MPolyIdeal{T}, J::MPolyIdeal{T}) where T
+  singular_assure(I)
+  singular_assure(J)
+  K, _ = Singular.saturation2(I.gens.S, J.gens.S)
+  return MPolyIdeal(base_ring(I), K)
+end
+
 #######################################################
 @doc raw"""
     saturation_with_index(I::MPolyIdeal{T}, J::MPolyIdeal{T}) where T