Deprecate is_FGP_Module, is_FilteredVectorSpace, is_FreeQuadraticModule, is_FreeModule, is_FreeModuleHomspace, is_MatrixSpace, is_Module, is_VectorSpace, is_VectorSpaceHomspace

src/sage/geometry/polyhedron/parent.py

@@ -14,7 +14,7 @@
 from sage.structure.parent import Parent
 from sage.structure.element import get_coercion_model
 from sage.structure.unique_representation import UniqueRepresentation
-from sage.modules.free_module import FreeModule, is_FreeModule
+from sage.modules.free_module import FreeModule, FreeModule_generic
 from sage.misc.cachefunc import cached_method, cached_function
 from sage.misc.lazy_import import lazy_import
 import sage.rings.abc
@@ -1009,7 +1009,7 @@ def _get_action_(self, other, op, self_is_left):
         from sage.structure.coerce_actions import ActedUponAction
         from sage.categories.action import PrecomposedAction
 
-        if op is operator.add and is_FreeModule(other):
+        if op is operator.add and isinstance(other, FreeModule_generic):
             base_ring = self._coerce_base_ring(other)
             extended_self = self.base_extend(base_ring)
             extended_other = other.base_extend(base_ring)

src/sage/groups/matrix_gps/finitely_generated.py

@@ -72,7 +72,7 @@
 from sage.groups.matrix_gps.group_element import is_MatrixGroupElement
 from sage.groups.matrix_gps.matrix_group import MatrixGroup_generic
 from sage.matrix.constructor import matrix
-from sage.matrix.matrix_space import is_MatrixSpace
+from sage.matrix.matrix_space import MatrixSpace
 from sage.misc.cachefunc import cached_method
 from sage.rings.integer_ring import ZZ
 from sage.structure.element import is_Matrix
@@ -130,7 +130,7 @@ def normalize_square_matrices(matrices):
         raise ValueError('not all matrices have the same size')
     gens = Sequence(gens, immutable=True)
     MS = gens.universe()
-    if not is_MatrixSpace(MS):
+    if not isinstance(MS, MatrixSpace):
         raise TypeError('all generators must be matrices')
     if MS.nrows() != MS.ncols():
         raise ValueError('matrices must be square')

src/sage/groups/matrix_gps/isometries.py

@@ -227,9 +227,9 @@ def _get_action_(self, S, op, self_on_left):
                 return GroupActionOnSubmodule(self, S)
             if S is self._invariant_quotient_module:
                 return GroupActionOnQuotientModule(self, S)
-            from sage.modules.fg_pid.fgp_module import is_FGP_Module
+            from sage.modules.fg_pid.fgp_module import FGP_Module_class
             T = self._invariant_quotient_module
-            if is_FGP_Module(S):
+            if isinstance(S, FGP_Module_class):
                 if S.is_submodule(T):
                     V = S.V()
                     if all(V == V * f.matrix() for f in self.gens()):

src/sage/manifolds/subsets/pullback.py

@@ -16,7 +16,7 @@
 from sage.categories.sets_cat import Sets, EmptySetError
 from sage.categories.metric_spaces import MetricSpaces
 from sage.misc.lazy_import import lazy_import
-from sage.modules.free_module import is_FreeModule
+from sage.modules.free_module import FreeModule_generic
 from sage.rings.infinity import infinity, minus_infinity
 from sage.rings.integer_ring import ZZ
 from sage.rings.rational_field import QQ
@@ -829,7 +829,7 @@ def is_closed(self):
             # Regardless of their base_ring, we treat polyhedra as closed
             # convex subsets of R^n
             return True
-        elif is_FreeModule(self._codomain_subset) and self._codomain_subset.rank() != infinity:
+        elif isinstance(self._codomain_subset, FreeModule_generic) and self._codomain_subset.rank() != infinity:
             if self._codomain_subset.base_ring() in MetricSpaces().Complete():
                 # Closed topological vector subspace
                 return True

src/sage/matrix/action.pyx

@@ -66,8 +66,8 @@ AUTHOR:
 
 import operator
 
-from sage.matrix.matrix_space import MatrixSpace, is_MatrixSpace
-from sage.modules.free_module import FreeModule, is_FreeModule
+from sage.matrix.matrix_space import MatrixSpace
+from sage.modules.free_module import FreeModule, FreeModule_generic
 from sage.structure.coerce cimport coercion_model
 from sage.categories.homset import Hom, End
 
@@ -100,7 +100,7 @@ cdef class MatrixMulAction(Action):
          over Univariate Polynomial Ring in x over Rational Field
     """
     def __init__(self, G, S, is_left):
-        if not is_MatrixSpace(G):
+        if not isinstance(G, MatrixSpace):
             raise TypeError("Not a matrix space: %s" % G)
         if isinstance(S, SchemeHomset_generic):
             if G.base_ring() is not S.domain().base_ring():
@@ -160,7 +160,7 @@ cdef class MatrixMatrixAction(MatrixMulAction):
         example is good practice.
     """
     def __init__(self, G, S):
-        if not is_MatrixSpace(S):
+        if not isinstance(S, MatrixSpace):
             raise TypeError("Not a matrix space: %s" % S)
 
         MatrixMulAction.__init__(self, G, S, True)
@@ -304,7 +304,7 @@ cdef class MatrixVectorAction(MatrixMulAction):
             ...
             TypeError: incompatible dimensions 3, 4
             """
-        if not is_FreeModule(S):
+        if not isinstance(S, FreeModule_generic):
             raise TypeError("Not a free module: %s" % S)
         MatrixMulAction.__init__(self, G, S, True)
 
@@ -355,7 +355,7 @@ cdef class VectorMatrixAction(MatrixMulAction):
             ...
             TypeError: incompatible dimensions 5, 3
         """
-        if not is_FreeModule(S):
+        if not isinstance(S, FreeModule_generic):
             raise TypeError("Not a free module: %s" % S)
         MatrixMulAction.__init__(self, G, S, False)
 

src/sage/matrix/matrix2.pyx

@@ -5786,7 +5786,7 @@ cdef class Matrix(Matrix1):
             sage: t.decomposition_of_subspace(v, check_restrict=False) == t.decomposition_of_subspace(v)                # needs sage.libs.pari
             True
         """
-        if not sage.modules.free_module.is_FreeModule(M):
+        if not isinstance(M, sage.modules.free_module.FreeModule_generic):
             raise TypeError("M must be a free module.")
         if not self.is_square():
             raise ArithmeticError("self must be a square matrix")

src/sage/matrix/matrix_space.py

@@ -74,12 +74,18 @@ def is_MatrixSpace(x):
         sage: MS = MatrixSpace(QQ,2)
         sage: A = MS.random_element()
         sage: is_MatrixSpace(MS)
+        doctest:warning...
+        DeprecationWarning: the function is_MatrixSpace is deprecated;
+        use 'isinstance(..., MatrixSpace)' instead
+        See https://github.com/sagemath/sage/issues/37924 for details.
         True
         sage: is_MatrixSpace(A)
         False
         sage: is_MatrixSpace(5)
         False
     """
+    from sage.misc.superseded import deprecation
+    deprecation(37924, "the function is_MatrixSpace is deprecated; use 'isinstance(..., MatrixSpace)' instead")
     return isinstance(x, MatrixSpace)
 
 
@@ -1265,10 +1271,10 @@ def _get_action_(self, S, op, self_on_left):
             if op is operator.mul:
                 from . import action as matrix_action
                 if self_on_left:
-                    if is_MatrixSpace(S):
+                    if isinstance(S, MatrixSpace):
                         # matrix multiplications
                         return matrix_action.MatrixMatrixAction(self, S)
-                    elif sage.modules.free_module.is_FreeModule(S):
+                    elif isinstance(S, sage.modules.free_module.FreeModule_generic):
                         return matrix_action.MatrixVectorAction(self, S)
                     elif isinstance(S, SchemeHomset_points):
                         return matrix_action.MatrixSchemePointAction(self, S)
@@ -1278,10 +1284,10 @@ def _get_action_(self, S, op, self_on_left):
                         # action of base ring
                         return sage.structure.coerce_actions.RightModuleAction(S, self)
                 else:
-                    if is_MatrixSpace(S):
+                    if isinstance(S, MatrixSpace):
                         # matrix multiplications
                         return matrix_action.MatrixMatrixAction(S, self)
-                    elif sage.modules.free_module.is_FreeModule(S):
+                    elif isinstance(S, sage.modules.free_module.FreeModule_generic):
                         return matrix_action.VectorMatrixAction(self, S)
                     elif isinstance(S, SchemeHomset_generic):
                         return matrix_action.PolymapMatrixAction(self, S)

src/sage/modular/abvar/abvar.py

@@ -51,7 +51,7 @@
 from sage.modular.modsym.modsym import ModularSymbols
 from sage.modular.modsym.space import ModularSymbolsSpace
 from sage.modular.quatalg.brandt import BrandtModule
-from sage.modules.free_module import is_FreeModule
+from sage.modules.free_module import FreeModule_generic
 from sage.modules.free_module_element import vector
 from sage.rings.fast_arith import prime_range
 from sage.rings.infinity import infinity
@@ -4009,7 +4009,7 @@ def __init__(self, groups, lattice=None, base_field=QQ, is_simple=None, newform_
             lattice = ZZ**(2 * self._ambient_dimension())
         if check:
             n = self._ambient_dimension()
-            if not is_FreeModule(lattice):
+            if not isinstance(lattice, FreeModule_generic):
                 raise TypeError("lattice must be a free module")
             if lattice.base_ring() != ZZ:
                 raise TypeError("lattice must be over ZZ")

src/sage/modular/abvar/finite_subgroup.py

@@ -103,7 +103,7 @@
 from sage.misc.lazy_import import lazy_import
 from sage.modular.abvar.torsion_point import TorsionPoint
 from sage.modules.module import Module
-from sage.modules.free_module import is_FreeModule
+from sage.modules.free_module import FreeModule_generic
 from sage.structure.gens_py import abelian_iterator
 from sage.structure.sequence import Sequence
 from sage.structure.richcmp import richcmp_method, richcmp
@@ -871,7 +871,7 @@ def __init__(self, abvar, lattice, field_of_definition=None, check=True):
             from sage.rings.qqbar import QQbar as field_of_definition
         if check:
             from .abvar import is_ModularAbelianVariety
-            if not is_FreeModule(lattice) or lattice.base_ring() != ZZ:
+            if not isinstance(lattice, FreeModule_generic) or lattice.base_ring() != ZZ:
                 raise TypeError("lattice must be a free module over ZZ")
             if not is_ModularAbelianVariety(abvar):
                 raise TypeError("abvar must be a modular abelian variety")

src/sage/modular/hecke/ambient_module.py

@@ -22,7 +22,7 @@
 from . import module
 from . import submodule
 
-from sage.modules.free_module import FreeModule, is_FreeModule
+from sage.modules.free_module import FreeModule, FreeModule_generic
 from sage.rings.integer import Integer
 
 import sage.arith.all as arith
@@ -927,7 +927,7 @@ def submodule(self, M, Mdual=None, check=True):
             Modular Forms subspace of dimension 2 of Modular Forms space of dimension 3 for Congruence Subgroup Gamma0(37) of weight 2 over Rational Field
         """
         if check:
-            if not is_FreeModule(M):
+            if not isinstance(M, FreeModule_generic):
                 V = self.free_module()
                 if isinstance(M, (list, tuple)):
                     M = V.span([V(x.element()) for x in M])

src/sage/modular/hecke/submodule.py

@@ -22,7 +22,7 @@
 import sage.arith.all as arith
 from sage.misc.verbose import verbose
 from sage.misc.cachefunc import cached_method
-from sage.modules.free_module import is_FreeModule
+from sage.modules.free_module import FreeModule_generic
 from sage.structure.richcmp import richcmp_method, richcmp_not_equal
 
 from . import module
@@ -81,7 +81,7 @@ def __init__(self, ambient, submodule, dual_free_module=None, check=True):
         from . import ambient_module
         if not isinstance(ambient, ambient_module.AmbientHeckeModule):
             raise TypeError("ambient must be an ambient Hecke module")
-        if not is_FreeModule(submodule):
+        if not isinstance(submodule, FreeModule_generic):
             raise TypeError("submodule must be a free module")
         if not submodule.is_submodule(ambient.free_module()):
             raise ValueError("submodule must be a submodule of the ambient free module")
@@ -96,7 +96,7 @@ def __init__(self, ambient, submodule, dual_free_module=None, check=True):
                                                 ambient.level(),
                                                 ambient.weight())
         if dual_free_module is not None:
-            if not is_FreeModule(dual_free_module):
+            if not isinstance(dual_free_module, FreeModule_generic):
                 raise TypeError("dual_free_module must be a free module")
             if dual_free_module.rank() != submodule.rank():
                 raise ArithmeticError("dual_free_module must have the same rank as submodule")
@@ -912,7 +912,7 @@ def submodule(self, M, Mdual=None, check=True):
             sage: S.submodule(S[0].free_module())
             Modular Symbols subspace of dimension 2 of Modular Symbols space of dimension 18 for Gamma_0(18) of weight 4 with sign 0 over Rational Field
         """
-        if not is_FreeModule(M):
+        if not isinstance(M, FreeModule_generic):
             V = self.ambient_module().free_module()
             if isinstance(M, (list, tuple)):
                 M = V.span([V(x.element()) for x in M])

src/sage/modular/modsym/ambient.py

@@ -88,7 +88,7 @@ class ``ModularSymbolsAmbient``, derived from
                                                    ManinSymbolList_gamma1,
                                                    ManinSymbolList_gamma_h,
                                                    ManinSymbolList_character)
-from sage.modules.free_module import is_FreeModule
+from sage.modules.free_module import FreeModule_generic
 from sage.modules.free_module_element import FreeModuleElement
 from sage.rings.integer import Integer
 from sage.rings.integer_ring import ZZ
@@ -2133,7 +2133,7 @@ def submodule(self, M, dual_free_module=None, check=True):
            Stein, 2007-07-27
         """
         if check:
-            if not is_FreeModule(M):
+            if not isinstance(M, FreeModule_generic):
                 V = self.free_module()
                 if not isinstance(M, (list, tuple)):
                     M = M.gens()

src/sage/modules/fg_pid/fgp_module.py

@@ -214,7 +214,7 @@
 from itertools import product
 
 from sage.modules.module import Module
-from sage.modules.free_module import is_FreeModule
+from sage.modules.free_module import FreeModule_generic
 from sage.structure.all import parent
 from sage.structure.sequence import Sequence
 from .fgp_element import DEBUG, FGP_Element
@@ -280,10 +280,16 @@ def is_FGP_Module(x):
         sage: V = span([[1/2,1,1],[3/2,2,1],[0,0,1]],ZZ)
         sage: W = V.span([2*V.0 + 4*V.1, 9*V.0 + 12*V.1, 4*V.2]); Q = V/W
         sage: sage.modules.fg_pid.fgp_module.is_FGP_Module(V)
+        doctest:warning...
+        DeprecationWarning: the function is_FGP_Module is deprecated;
+        use 'isinstance(..., FGP_Module_class)' instead
+        See https://github.com/sagemath/sage/issues/37924 for details.
         False
         sage: sage.modules.fg_pid.fgp_module.is_FGP_Module(Q)
         True
     """
+    from sage.misc.superseded import deprecation
+    deprecation(37924, "the function is_FGP_Module is deprecated; use 'isinstance(..., FGP_Module_class)' instead")
     return isinstance(x, FGP_Module_class)
 
 
@@ -356,9 +362,9 @@ def __init__(self, V, W, check=True):
             <class 'sage.modules.fg_pid.fgp_module.FGP_Module_class_with_category'>
         """
         if check:
-            if not is_FreeModule(V):
+            if not isinstance(V, FreeModule_generic):
                 raise TypeError("V must be a FreeModule")
-            if not is_FreeModule(W):
+            if not isinstance(W, FreeModule_generic):
                 raise TypeError("W must be a FreeModule")
             if not W.is_submodule(V):
                 raise ValueError("W must be a submodule of V")
@@ -441,7 +447,7 @@ def _coerce_map_from_(self, S):
             sage: Q._coerce_map_from_(V.scale(2))
             True
         """
-        if is_FGP_Module(S):
+        if isinstance(S, FGP_Module_class):
             return S.has_canonical_map_to(self)
         return self._V.has_coerce_map_from(S)
 
@@ -500,8 +506,8 @@ def __truediv__(self, other):
             sage: Q/Q
             Finitely generated module V/W over Integer Ring with invariants ()
         """
-        if not is_FGP_Module(other):
-            if is_FreeModule(other):
+        if not isinstance(other, FGP_Module_class):
+            if isinstance(other, FreeModule_generic):
                 other = other / other.zero_submodule()
             else:
                 raise TypeError("other must be an FGP module")
@@ -525,7 +531,7 @@ def __eq__(self, other):
             sage: Q == V/V.zero_submodule()
             False
         """
-        if not is_FGP_Module(other):
+        if not isinstance(other, FGP_Module_class):
             return False
         return self._V == other._V and self._W == other._W
 
@@ -745,7 +751,7 @@ def submodule(self, x):
             ...
             ValueError: x.V() must be contained in self's V.
         """
-        if is_FGP_Module(x):
+        if isinstance(x, FGP_Module_class):
             if not x._W.is_submodule(self._W):
                 raise ValueError("x.W() must be contained in self's W.")
 
@@ -759,7 +765,7 @@ def submodule(self, x):
             raise TypeError("x must be a list, tuple, or FGP module")
 
         x = Sequence(x)
-        if is_FGP_Module(x.universe()):
+        if isinstance(x.universe(), FGP_Module_class):
             # TODO: possibly inefficient in some cases
             x = [self(v).lift() for v in x]
         V = self._V.submodule(x) + self._W
@@ -791,7 +797,7 @@ def has_canonical_map_to(self, A):
             False
 
         """
-        if not is_FGP_Module(A):
+        if not isinstance(A, FGP_Module_class):
             return False
         if self.cardinality() == 0 and self.base_ring() == A.base_ring():
             return True
@@ -1598,7 +1604,7 @@ def hom(self, im_gens, codomain=None, check=True):
                 N = codomain
                 im_gens = Sequence(im_gens, universe=N)
 
-        if is_FreeModule(N):
+        if isinstance(N, FreeModule_generic):
             # If im_smith_gens are not in an R-module, but are in a Free-module,
             # then we quotient out by the 0 submodule and get an R-module.
             N = FGP_Module(N, N.zero_submodule(), check=DEBUG)
@@ -2047,7 +2053,7 @@ def random_fgp_morphism_0(*args, **kwds):
         sage: mor = fgp.random_fgp_morphism_0(4)
         sage: mor.domain() == mor.codomain()
         True
-        sage: fgp.is_FGP_Module(mor.domain())
+        sage: isinstance(mor.domain(), fgp.FGP_Module_class)
         True
 
     Each generator is sent to a random multiple of itself::