sage.rings.polynomial.laurent_polynomial_ring_base: Split out from .laurent_polynomial_ring

src/doc/en/reference/polynomial_rings/index.rst

@@ -45,6 +45,7 @@ Laurent Polynomials
 .. toctree::
    :maxdepth: 1
 
+   sage/rings/polynomial/laurent_polynomial_ring_base
    sage/rings/polynomial/laurent_polynomial_ring
    sage/rings/polynomial/laurent_polynomial
    sage/rings/polynomial/omega

src/sage/categories/pushout.py

@@ -1760,9 +1760,10 @@ def _apply_functor(self, R):
             Multivariate Laurent Polynomial Ring in s, t over Rational Field
 
         """
-        from sage.rings.polynomial.laurent_polynomial_ring import LaurentPolynomialRing, is_LaurentPolynomialRing
-        if self.multi_variate and is_LaurentPolynomialRing(R):
-            return LaurentPolynomialRing(R.base_ring(), (list(R.variable_names()) + [self.var]))
+        from sage.rings.polynomial.laurent_polynomial_ring import LaurentPolynomialRing
+        from sage.rings.polynomial.laurent_polynomial_ring_base import LaurentPolynomialRing_generic
+        if self.multi_variate and isinstance(R, LaurentPolynomialRing_generic):
+            return LaurentPolynomialRing(R.base_ring(), list(R.variable_names()) + [self.var])
         else:
             return LaurentPolynomialRing(R, self.var)
 

src/sage/rings/fraction_field.py

@@ -313,7 +313,7 @@ def _coerce_map_from_(self, S):
         """
         from sage.rings.rational_field import QQ
         from sage.rings.number_field.number_field_base import NumberField
-        from sage.rings.polynomial.laurent_polynomial_ring import \
+        from sage.rings.polynomial.laurent_polynomial_ring_base import \
             LaurentPolynomialRing_generic
 
         if S is self._R:

src/sage/rings/laurent_series_ring.py

@@ -623,9 +623,10 @@ def _coerce_map_from_(self, P):
         A = self.base_ring()
         from sage.rings.polynomial.polynomial_ring import is_PolynomialRing
         from sage.rings.power_series_ring import is_PowerSeriesRing
-        from sage.rings.polynomial.laurent_polynomial_ring import is_LaurentPolynomialRing
+        from sage.rings.polynomial.laurent_polynomial_ring_base import LaurentPolynomialRing_generic
+
         if ((is_LaurentSeriesRing(P) or
-             is_LaurentPolynomialRing(P) or
+             isinstance(P, LaurentPolynomialRing_generic) or
              is_PowerSeriesRing(P) or
              is_PolynomialRing(P))
             and P.variable_name() == self.variable_name()

src/sage/rings/localization.py

@@ -669,8 +669,9 @@ def __init__(self, base_ring, extra_units, names=None, normalize=True, category=
         if not type(extra_units) is list:
             extra_units = [extra_units]
 
-        from sage.rings.polynomial.laurent_polynomial_ring import is_LaurentPolynomialRing
-        if is_LaurentPolynomialRing(base_ring):
+        from sage.rings.polynomial.laurent_polynomial_ring_base import LaurentPolynomialRing_generic
+
+        if isinstance(base_ring, LaurentPolynomialRing_generic):
             extra_units += list(base_ring.gens())
             base_ring = base_ring.polynomial_ring()