Changes between Version 8 and Version 13 of Ticket #24431

Timestamp:

Jan 3, 2018, 4:56:02 PM (5 years ago)

Author:

tscrim

Comment:

I understand now the reason why that change is needed. Thanks. (Although I don't quite understand why that pushout is no longer allowed, but that's okay.)

Just remove the unneeded import of LaurentPolynomialRing and the \'s here

@@ -410,7 +565,11 @@ class LaurentSeriesRing_generic(UniqueRepresentation, ring.CommutativeRing):
 
         from sage.rings.polynomial.polynomial_ring import is_PolynomialRing
         from sage.rings.power_series_ring import is_PowerSeriesRing
-        if ((is_LaurentSeriesRing(P) or is_PowerSeriesRing(P) or is_PolynomialRing(P))
+        from sage.rings.polynomial.laurent_polynomial_ring import is_LaurentPolynomialRing
+        if ((is_LaurentSeriesRing(P) or \
+             is_LaurentPolynomialRing(P) or \
+             is_PowerSeriesRing(P) or \
+             is_PolynomialRing(P))
             and P.variable_name() == self.variable_name()
             and A.has_coerce_map_from(P.base_ring())):
             return True

and you can set a positive review on my behalf.