word 'inverse' is derived from that means 'turned upside down', 'overturned'. This may take its origin from the case of fractions, where the (multiplicative) inverse is obtained by exchanging the numerator and the denominator (the inverse of is ).

Definitions and basic properties

The concepts of inverse element and invertible element are commonly defined for binary operations that are everywhere defined (that is, the operation is

1.Previous
3.Next