@@ -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