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PolyAlgebraHom    --    homomorphism of polynomial algebras


Syntax 
PolyAlgebraHom(Domain: RING, Codomain: RING, images: LIST): RINGHOM
PolyAlgebraHom(Domain: RING, Codomain: RING, images: STRING): RINGHOM

Description
These functions create the homomorphism of (polynomial) algebras from R to S with the same ring of coefficients. This is uniquely defined by the images of the indeterminates of R which are specified by the entries of images. If the rings of coefficients are not the same, consider using PolyRingHom .

This is a cleaner mathematical implementation of the function image [OBSOLESCENT] in CoCoA-4.

Example 
/**/  use R ::= QQ[x,y,z];
/**/  S ::= QQ[x[1..3]];
/**/  phi := PolyAlgebraHom(R, S, indets(S));
/**/  phi(x^2-y);
x[1]^2 -x[2]

/**/  S ::= QQ[a];
/**/  phi := PolyAlgebraHom(R, S, "a,1,0");
/**/  phi(x^2-y);
a^2 -1

/**/  phi := PolyAlgebraHom(R, QQ, "2,1,0"); --> evaluate at [2,1,0]
/**/  phi(x^2-y);
3

See Also