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2.10.1 Introduction to RINGHOM
containing an INT or a RAT can be immediately
used within any RING.
But an object
of other types, such as RINGELEM, IDEAL, MAT,.. can be
used only within its own RING,
Such an object can be mapped into another RING using a
Most likely, the only function you need to use is just
which returns the canonical homomorphism
between two rings (if there is one).
Given a RINGHOM
is a RINGELEM,
is a LIST or MAT.
However, there are also a few handy shortcuts silently determining and
applying a homomorphism:
map the argument into the given ring
into a new matrix in the ring
Another shortcut is
(easy, but slow).
NOTE: all CoCoA functions should be smart enough to take into account
the RING in which their value was defined, for example
are NOT YET IMPLEMENTED.