Initial commit of fix for sagemath#37108

trevorkarn · Jan 23, 2024 · 3e06400 · 3e06400
1 parent 3dd953c
commit 3e06400
Showing 1 changed file with 21 additions and 2 deletions.
diff --git a/src/sage/algebras/exterior_algebra_groebner.pyx b/src/sage/algebras/exterior_algebra_groebner.pyx
@@ -477,13 +477,32 @@ cdef class GroebnerStrategy:
             0
             sage: I._groebner_strategy.reduce(E.zero())
             0
+
+        Check #37108 is fixed::
+
+            sage: E = ExteriorAlgebra(QQ, 6)
+            ....: E.inject_variables(verbose=False)
+            ....: gens = [-e0*e1*e2 + e0*e1*e5 - e0*e2*e3 - e0*e3*e5 + e1*e2*e3 + e1*e3*e5,
+            ....:  e1*e2 - e1*e5 + e2*e5,
+            ....:  e0*e2 - e0*e4 + e2*e4,
+            ....:  e3*e4 - e3*e5 + e4*e5,
+            ....:  e0*e1 - e0*e3 + e1*e3]
+            ....: I = E.ideal(gens)
+            ....: S = E.quo(I)
+            ....: I.reduce(e1*e3*e4*e5)
+            0
         """
         if not f:
             return f
         # Make a copy to mutate
         f = type(f)(f._parent, copy(f._monomial_coefficients))
-        for g in self.groebner_basis:
-            self.reduce_single(f, g)
+        was_reduced = True
+        while was_reduced:
+            was_reduced = False
+            for g in self.groebner_basis:
+                was_reduced = self.reduce_single(f, g)
+                if was_reduced:
+                    break
         return f
 
     cdef bint reduce_single(self, CliffordAlgebraElement f, CliffordAlgebraElement g) except -1: