A transformation *alpha* on *n* points is completely defined by its list
of images. It is stored as a record with the following category
components.

`isTransformation`

:-

is always set to`true`

.

`domain`

:-

is always set to`Transformations`

.

Moreover it has the identification component

`images`

:

containing the list of images in such a way that*i^alpha = alpha.'images[i]'*for all*i leq n*.

The multiplication of these transformations can be efficiently
implemented by using the sublist operator `{ }`

. The product

of two transformations `r` *
`l``l` and `r` can be computed as
`Transformation( `

. Note that the order has
been chosen to have transformations act from the right on their domain.
`r`.images{ `l`.images } )