5 files changed, 8 insertions, 9 deletions
diff --git a/mdpoly/__init__.py b/mdpoly/__init__.py
index 1ac17a5..c341cb1 100644
--- a/mdpoly/__init__.py
+++ b/mdpoly/__init__.py
@@ -105,7 +105,7 @@ TODO: data structure(s) that represent the polynomial
 # internal classes imported with underscore because 
 # they should not be exposed to the end users
 
-from .abc import (Shape as _Shape)
+from .index import (Shape as _Shape)
 
 from .expressions.poly import (PolyConst as _PolyConst, PolyVar as _PolyVar, PolyParam as _PolyParam)
 from .expressions.matrix import (MatConst as _MatConst, MatVar as _MatVar, MatParam as _MatParam)
diff --git a/mdpoly/abc.py b/mdpoly/abc.py
index cd90f85..657adf7 100644
--- a/mdpoly/abc.py
+++ b/mdpoly/abc.py
@@ -11,10 +11,11 @@ from dataclassabc import dataclassabc
 
 from .constants import NUMERICS_EPS
 from .errors import AlgebraicError
+from .index import Shape
 from .util import iszero
 
 if TYPE_CHECKING:
-    from .index import Number, Shape, MatrixIndex, PolyIndex
+    from .index import Number, MatrixIndex, PolyIndex
     from .state import State
 
 
diff --git a/mdpoly/expressions/matrix.py b/mdpoly/expressions/matrix.py
index 65f86c2..cd38383 100644
--- a/mdpoly/expressions/matrix.py
+++ b/mdpoly/expressions/matrix.py
@@ -9,8 +9,6 @@ from ..abc import Expr, Var, Const, Param, Algebra
 from ..index import MatrixIndex, PolyIndex, PolyVarIndex
 from ..errors import MissingParameters
 
-from .. import operations
-
 if TYPE_CHECKING:
     from ..abc import ReprT
     from ..index import Shape, Number
@@ -124,7 +122,6 @@ class MatConst(Const, MatrixExpr):
         return self.name
 
 
-
 T = TypeVar("T", bound=Var)
 
 @dataclassabc(frozen=True)
diff --git a/mdpoly/expressions/poly.py b/mdpoly/expressions/poly.py
index 3fe83ca..6e0308b 100644
--- a/mdpoly/expressions/poly.py
+++ b/mdpoly/expressions/poly.py
@@ -1,10 +1,11 @@
 from __future__ import annotations
 from typing import TYPE_CHECKING
 
-from typing import Type, Iterable
+from typing import Type, Iterable, cast
 from functools import reduce
 from itertools import chain, combinations_with_replacement
 from dataclassabc import dataclassabc
+from operator import mul as opmul
 
 from ..abc import Expr, Var, Const, Param, Algebra, ReprT
 from ..index import Shape, MatrixIndex, PolyIndex, PolyVarIndex, Number
@@ -62,7 +63,7 @@ class PolyRingExpr(Expr):
         # Ignore typecheck because dataclassabc has no typing stub
         vars_and_const = chain(variables, (PolyConst(1),)) # type: ignore[call-arg]
         for comb in combinations_with_replacement(vars_and_const, max_degree):
-            yield cast(PolyRingExpr, reduce(operator.mul, comb))
+            yield cast(PolyRingExpr, reduce(opmul, comb))
 
     # --- Operator Overloading ---
 
diff --git a/mdpoly/representations.py b/mdpoly/representations.py
index 32c75d7..1efe286 100644
--- a/mdpoly/representations.py
+++ b/mdpoly/representations.py
@@ -4,10 +4,10 @@ from typing import TYPE_CHECKING
 from typing import Iterable
 import numpy as np
 
+from .abc import Repr 
+
 if TYPE_CHECKING:
     import numpy.typing as npt
-
-    from .abc import Repr 
     from .index import Number, Shape, MatrixIndex, PolyIndex