# Difference between revisions of "HowTo:Use Modular Numbers"

From CoCoAWiki

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Line 9: | Line 9: | ||

FALSE | FALSE | ||

------------------------------- | ------------------------------- | ||

− | Moreover this throws an error | + | Moreover this command throws an error |

Use R::=Z/(5); | Use R::=Z/(5); | ||

=== Answer === | === Answer === | ||

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------------------------------- | ------------------------------- | ||

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)? ;-) | 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++) | + | If you want to use 5 as a modular number you should either use this syntax (similar to C/C++) |

5 % 5; | 5 % 5; | ||

0 % 5 | 0 % 5 | ||

Line 25: | Line 25: | ||

0 | 0 | ||

------------------------------- | ------------------------------- | ||

+ | The creation of a polynomial ring with no indeterminated has been disabled to highlight this (unexpected?) behaviour. |

## Revision as of 16:48, 29 November 2005

## Modular Numbers

### Question

What's wrong in this?

Use R::=Z/(5)[x]; 5x+2y; 2y ------------------------------- 5=0; FALSE -------------------------------

Moreover this command 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 either 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 -------------------------------

The creation of a polynomial ring with no indeterminated has been disabled to highlight this (unexpected?) behaviour.