# ApCoCoA-1:NCo.SetRelations

From ApCoCoAWiki

This article is about a function from ApCoCoA-1. |

## NCo.SetRelations

Set relations for a finitely presented monoid ring.

### Syntax

NCo.SetRelations(R:LIST)

### Description

Before calling the function, please set ring environment alphabet (or set of indeterminates) `X` through the functions NCo.SetX. For more information, please check the relevant functions.

@param

*R:*a finite set of relations. It is of LIST type. Each element in Relations is of the form [W1, W2], where W1 and W2 are words in`<X>`. Each word is represented as a STRING. For example, the word`xy^2x`is represented as "xyyx", and the identity is represented as the empty string "". Thus, the relation`(yx, xy)`is represented as ["yx", "xy"], and the set of relations`{(yx, xy),(zx,xz),(zy,yz)}`is represented as [["yx", "xy"],["zx", "xz"],["zy", "yz"]].

#### Example

NCo.RingEnv(); Coefficient ring : Q Ordering : LLEX ------------------------------- NCo.SetX("abc"); R:=[["ba","ab"], ["ca","ac"], ["cb","bc"]]; --ba=ab, ca=ac, cb=bc NCo.SetRelations(R); NCo.RingEnv(); Coefficient ring : Q Alphabet : abc Ordering : LLEX Relations : [["ba", "ab"], ["ca", "ac"], ["cb", "bc"]] -- relations generated by {ba=ab, ca=ac, cb=bc} -------------------------------

### See also