Difference between revisions of "CoCoA:Use"
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Latest revision as of 10:02, 24 October 2007
Use
command for making a ring active
Description
This command makes a ring active, i.e. makes a ring the current ring.
The command
Use N ::= E; where E is a ring, is a shorthand for N ::= E; Use N;
If you want to change the ring inside a function you should
call <ttref>Using</ttref> instead.
Example
Use S ::= Q[x,y,z]; RingEnv(); S ------------------------------- T ::= Z/(3)[a,b]; Use T; RingEnv(); T ------------------------------- Use Q[u]; -- note that <quotes>Use</quotes> can be used w/out a ring identifier RingEnv(); CurrentRingEnv ------------------------------- CurrentRing(); Q[u] -------------------------------
Syntax
Use N where N is either the identifier of an existing ring or a ring itself.
<type>ring</type>