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D.2.6.1 changechar

Procedure from library ring.lib (see section ring_lib).

Usage:

changechar(newr,c[,r]); newr,c=strings, r=ring

Create:

create a new ring with name ‘newr‘ and make it the basering if r is an existing ring [default: r=basering].
The new ring differs from the old ring only in the characteristic. If, say, (newr,c) = ("R","0,A") and the ring r exists, the new basering will have name R, characteristic 0 and one parameter A.

Return:

No return value

Note:

Works for qrings if map from old_char to new_char is implemented This proc uses ’execute’ or calls a procedure using ’execute’. If you use it in your own proc, let the local names of your proc start with @.

Example:

LIB "ring.lib";
ring r=0,(x,y,u,v),(dp(2),ds);
changechar("R","2,A"); R;"";
→ // basering is now R
→ //   characteristic : 2
→ //   1 parameter    : A 
→ //   minpoly        : 0
→ //   number of vars : 4
→ //        block   1 : ordering dp
→ //                  : names    x y 
→ //        block   2 : ordering ds
→ //                  : names    u v 
→ //        block   3 : ordering C
→ 
changechar("R1","32003",R); R1;
→ // basering is now R1
→ //   characteristic : 32003
→ //   number of vars : 4
→ //        block   1 : ordering dp
→ //                  : names    x y 
→ //        block   2 : ordering ds
→ //                  : names    u v 
→ //        block   3 : ordering C
kill R,R1;
if(system("with","Namespaces")) {
if( nameof(Current) == "Ring" ) {
kill Top::R,Top::R1;
} else {
kill Ring::R,Ring::R1;
}
}

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            User manual for Singular version 2-0-4, October 2002, generated by texinfo.