diff --git a/src/tensortrax/__about__.py b/src/tensortrax/__about__.py
index 35a1fb7..993bad7 100644
--- a/src/tensortrax/__about__.py
+++ b/src/tensortrax/__about__.py
@@ -2,4 +2,4 @@
 tensorTRAX: Math on (Hyper-Dual) Tensors with Trailing Axes.
 """
 
-__version__ = "0.8.5"
+__version__ = "0.9.0"
diff --git a/src/tensortrax/_tensor.py b/src/tensortrax/_tensor.py
index 69eb99f..05c1dc8 100644
--- a/src/tensortrax/_tensor.py
+++ b/src/tensortrax/_tensor.py
@@ -176,12 +176,14 @@ def __add__(self, B):
             δx = δ(A) + δ(B)
             Δx = Δ(A) + Δ(B)
             Δδx = Δδ(A) + Δδ(B)
+            ntrax = min(A.ntrax, B.ntrax)
         else:
             x = f(A) + B
             δx = δ(A)
             Δx = Δ(A)
             Δδx = Δδ(A)
-        return Tensor(x=x, δx=δx, Δx=Δx, Δδx=Δδx, ntrax=A.ntrax)
+            ntrax = A.ntrax
+        return Tensor(x=x, δx=δx, Δx=Δx, Δδx=Δδx, ntrax=ntrax)
 
     def __sub__(self, B):
         A = self
@@ -190,12 +192,14 @@ def __sub__(self, B):
             δx = δ(A) - δ(B)
             Δx = Δ(A) - Δ(B)
             Δδx = Δδ(A) - Δδ(B)
+            ntrax = min(A.ntrax, B.ntrax)
         else:
             x = f(A) - B
             δx = δ(A)
             Δx = Δ(A)
             Δδx = Δδ(A)
-        return Tensor(x=x, δx=δx, Δx=Δx, Δδx=Δδx, ntrax=A.ntrax)
+            ntrax = A.ntrax
+        return Tensor(x=x, δx=δx, Δx=Δx, Δδx=Δδx, ntrax=ntrax)
 
     def __rsub__(self, B):
         return -self.__sub__(B)
@@ -207,12 +211,14 @@ def __mul__(self, B):
             δx = δ(A) * f(B) + f(A) * δ(B)
             Δx = Δ(A) * f(B) + f(A) * Δ(B)
             Δδx = Δ(A) * δ(B) + δ(A) * Δ(B) + Δδ(A) * f(B) + f(A) * Δδ(B)
+            ntrax = min(A.ntrax, B.ntrax)
         else:
             x = f(A) * B
             δx = δ(A) * B
             Δx = Δ(A) * B
             Δδx = Δδ(A) * B
-        return Tensor(x=x, δx=δx, Δx=Δx, Δδx=Δδx, ntrax=A.ntrax)
+            ntrax = A.ntrax
+        return Tensor(x=x, δx=δx, Δx=Δx, Δδx=Δδx, ntrax=ntrax)
 
     def __truediv__(self, B):
         A = self
@@ -403,7 +409,7 @@ def einsum3(subscripts, *operands):
             + _einsum(f(A), δ(B), Δ(C))
             + _einsum(f(A), Δ(B), δ(C))
         )
-        ntrax = A.ntrax
+        ntrax = min(A.ntrax, B.ntrax, C.ntrax)
     elif (
         isinstance(A, Tensor)
         and not isinstance(B, Tensor)
@@ -444,7 +450,7 @@ def einsum3(subscripts, *operands):
             + _einsum(δ(A), Δ(B), C)
             + _einsum(Δ(A), δ(B), C)
         )
-        ntrax = A.ntrax
+        ntrax = min(A.ntrax, B.ntrax)
     elif isinstance(A, Tensor) and not isinstance(B, Tensor) and isinstance(C, Tensor):
         x = _einsum(f(A), B, f(C))
         δx = _einsum(δ(A), B, f(C)) + _einsum(f(A), B, δ(C))
@@ -455,7 +461,7 @@ def einsum3(subscripts, *operands):
             + _einsum(δ(A), B, Δ(C))
             + _einsum(Δ(A), B, δ(C))
         )
-        ntrax = A.ntrax
+        ntrax = min(A.ntrax, C.ntrax)
     elif not isinstance(A, Tensor) and isinstance(B, Tensor) and isinstance(C, Tensor):
         x = _einsum(A, f(B), f(C))
         δx = _einsum(A, δ(B), f(C)) + _einsum(A, f(B), δ(C))
@@ -466,7 +472,7 @@ def einsum3(subscripts, *operands):
             + _einsum(A, δ(B), Δ(C))
             + _einsum(A, Δ(B), δ(C))
         )
-        ntrax = B.ntrax
+        ntrax = min(B.ntrax, C.ntrax)
     else:
         return _einsum(*operands)
 
@@ -488,7 +494,7 @@ def einsum2(subscripts, *operands):
             + _einsum(δ(A), Δ(B))
             + _einsum(Δ(A), δ(B))
         )
-        ntrax = A.ntrax
+        ntrax = min(A.ntrax, B.ntrax)
     elif isinstance(A, Tensor) and not isinstance(B, Tensor):
         x = _einsum(f(A), B)
         δx = _einsum(δ(A), B)
diff --git a/src/tensortrax/math/_math_tensor.py b/src/tensortrax/math/_math_tensor.py
index 016fc3b..3f81fdd 100644
--- a/src/tensortrax/math/_math_tensor.py
+++ b/src/tensortrax/math/_math_tensor.py
@@ -46,7 +46,7 @@ def array(object, dtype=None):
                 δx=np.array([δ(o) for o in object], dtype=dtype),
                 Δx=np.array([Δ(o) for o in object], dtype=dtype),
                 Δδx=np.array([Δδ(o) for o in object], dtype=dtype),
-                ntrax=object[0].ntrax,
+                ntrax=min([o.ntrax for o in object]),
             )
         else:
             return np.array(object, dtype=dtype)
@@ -286,7 +286,7 @@ def hstack(tup):
             δx=np.hstack([δ(A) for A in tup]),
             Δx=np.hstack([Δ(A) for A in tup]),
             Δδx=np.hstack([Δδ(A) for A in tup]),
-            ntrax=tup[0].ntrax,
+            ntrax=min([A.ntrax for A in tup]),
         )
     else:
         return np.hstack(tup)
@@ -301,7 +301,7 @@ def vstack(tup):
             δx=np.vstack([δ(A) for A in tup]),
             Δx=np.vstack([Δ(A) for A in tup]),
             Δδx=np.vstack([Δδ(A) for A in tup]),
-            ntrax=tup[0].ntrax,
+            ntrax=min([A.ntrax for A in tup]),
         )
     else:
         return np.vstack(tup)
@@ -316,7 +316,7 @@ def stack(arrays, axis=0):
             δx=np.stack([δ(A) for A in arrays], axis=axis),
             Δx=np.stack([Δ(A) for A in arrays], axis=axis),
             Δδx=np.stack([Δδ(A) for A in arrays], axis=axis),
-            ntrax=arrays[0].ntrax,
+            ntrax=min([A.ntrax for A in arrays]),
         )
     else:
         return np.stack(arrays, axis=0)