UnDeclareNonCommutative[a, b, ...] undeclares
a,b, ... to be noncommutative, i.e.,
DataType[a,b, ..., NonCommutative] is set to
False.
Overview, DataType, DeclareNonCommutative.
DeclareNonCommutative[x]As a side-effect of DeclareNonCommutative x
is declared to be of DataType
NonCommutative.
DataType[x, NonCommutative]\text{True}
The inverse operation is UnDeclareNonCommutative.
UnDeclareNonCommutative[x]
DataType[x, NonCommutative]\text{False}
DeclareNonCommutative[y, z]
DataType[y, z, NonCommutative]
```mathematica
$$\{\text{True},\text{True}\}$$
```mathematica
UnDeclareNonCommutative[y, z]
DataType[y, z, NonCommutative]\{\text{False},\text{False}\}