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bring in objects from another ring
BringIn(E: OBJECT): OBJECT
This function maps a polynomial (or a list, matrix of these) into the
current ring, preserving the names of the indeterminates.
This function is not implemented on ideals because might be
misleading: one might expect that bringing an ideal from
, while others might
expect the ideal generated by mapping the generators.
For example in the first case (x-y, x+y)
, in the second case returns an error.
So, if you want to map the generators of the ideal type
-- Changing characteristic from non-0 to 0 is NOT YET IMPLEMENTED in CoCoA-5
When mapping from a ring of finite characteristic to one of zero
characteristic then consistent choices of image for the coefficients
are made (i.e. if two coefficients are equal mod p then their images
will be equal).
/**/ RR ::= QQ[x[1..4],z,y];
/**/ SS ::= ZZ[z,y,x[1..2]];
/**/ use RR;
/**/ F := (x-y-z)^2; F;
x^2 -2*x*z +z^2 -2*x*y +2*z*y +y^2
/**/ use SS;
z^2 +2*z*y +y^2 -2*z*x -2*y*x +x^2
/**/ use R ::= QQ[x,y,z];
/**/ F := (1/2)*x^3 + (34/567)*x*y*z - 890; -- poly with rational coefficients
/**/ use S ::= ZZ/(101)[x,y,z];
-50*x^3 -19*x*y*z +19