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#

Natural Transformations

**Definition 3.6**

*A natural transformation from
to
is an assignment of an arrow
that associates to each object A in
an arrow
in Set such that, for any
-arrow
the following diagram commutes
*

*i.e.*

**natural transformation**.

From this diagram it is clear that the two arrows and turn the Y-picture of into the respective X-picture.

Cecilia Flori 2007-01-02