Difference between revisions of "CoCoA:HowTo:Use Modular Numbers"
From ApCoCoAWiki
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| Line 5: | Line 5: | ||
5x+2y; | 5x+2y; | ||
2y | 2y | ||
| − | ------------------------------- | + | ------------------------------- |
5=0; | 5=0; | ||
FALSE | FALSE | ||
| − | ------------------------------- | + | ------------------------------- |
Moreover this throws an error | Moreover this throws an error | ||
Use R::=Z/(5); | Use R::=Z/(5); | ||
=== Answer === | === Answer === | ||
| − | + | Type(5); | |
| − | INT | + | INT |
| − | ------------------------------- | + | ------------------------------- |
| − | 5 | + | 5 is an integer, and integers do not depend on the current ring: could you imagine what would happen to a For cycle over Z/(2)? ;-) |
| − | + | If you want to use 5 as a modular number you should use this syntax (similar to C/C++) | |
| − | + | 5 % 5; | |
| − | + | 0 % 5 | |
| − | + | ------------------------------- | |
| − | 0 % 5 | + | or embed your integer into the polynomial ring |
| − | ------------------------------- | + | Use R::=Z/(5)[x]; |
| − | + | Poly(5); | |
| − | + | 0 | |
| − | + | ------------------------------- | |
| − | 0 | ||
| − | ------------------------------- | ||
Revision as of 14:45, 29 November 2005
Modular Numbers
Question
What's wrong in this?
Use R::=Z/(5)[x]; 5x+2y; 2y ------------------------------- 5=0; FALSE -------------------------------
Moreover this throws an error
Use R::=Z/(5);
Answer
Type(5); INT -------------------------------
5 is an integer, and integers do not depend on the current ring: could you imagine what would happen to a For cycle over Z/(2)? ;-) If you want to use 5 as a modular number you should use this syntax (similar to C/C++)
5 % 5; 0 % 5 -------------------------------
or embed your integer into the polynomial ring
Use R::=Z/(5)[x]; Poly(5); 0 -------------------------------
