Reserved symbols that cannot represent a numerical value are invalid powers. By default, Maple assumes that an invalid power implies that the entire expression, for example,   is to be taken atomically (an expression that cannot be broken down into its component meanings) as an expression unto itself.

This error message occurs when you have attempted to raise an expression to an invalid power while Typesetting:-Settings(autoatomic=false).

Example 1:

The following value is identified as an atomic object.

Example 2:

The same value produces an error because autoatomic is set to false.

Solution: This automatic behavior can be disabled by setting the Typesetting[Settings] command to true, or via the Typesetting Rule Assistant.

2Dmath, 2DMathDetails, Typesetting[Settings]