# Difference between revisions of "ApCoCoA-1:DA.DiffTO"

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## Revision as of 11:24, 24 April 2009

## DA.DiffTO

Matrix corresponding to predefined differential term orderings.

### Syntax

DA.DiffTO(D:STRING):MATRIX

### Description

This function returns the matrix corresponding to the indicated term ordering D.

@param

*D*Name of a predefined differential term ordering.@return The matrix corresponding to the predefined term ordering.

#### Example

-- Assume that the current ring is given by Q[x[1..n,0..m]]. -- Then D can be one of the following values: -- "Lex": Lexicographic ordering with 1<x[1,0]<x[1,1]<x[1,2]<...<x[2,0]<x[2,1]<... -- "DegLex": S > T iff Deg(S) > Deg(T) or Deg(S) = Deg(T) and S >_Lex T -- "WLex": S > T iff Weight(S) > Weight(T) or Weight(S) = Weight(T) and S >_Lex T -- "Ord": Lexicographic ordering with 1<x[1,0]<x[2,0]<...<x[1,1]<x[2,1]<... -- "DegOrd": S > T iff Deg(S) > Deg(T) or Deg(S) = Deg(T) and S >_Ord T -- "WOrd": S > T iff Weight(S) > Weight(T) or Weight(S) = Weight(T) and S >_Ord T -- -- Use as follows: Use Q[x[1..1,0..20]]; Use Q[x[1..1,0..20]], Ord(DiffTO("Lex"));