# ApCoCoA-1:DA.InitialOfDer

From ApCoCoAWiki

Revision as of 14:07, 22 April 2009 by S schuster (talk | contribs) (ApCoCoA:Diffalg.InitialOfDer moved to ApCoCoA:DA.InitialOfDer: To comply with style principles.)

## DA.InitialOfDer

Computes the initial wrt. a given derivative.

### Syntax

DA.InitialOfDer(F:POLY, X:INDET):POLY

### Description

DA.InitialOfDer returns the polynomial leading coefficient of polynomial F regarded as polynomial in the derivative X.

@param F A differential polynomial.

@param X A indeterminate.

@return Initial of F wrt. X.

#### Example

Use Q[x[1..2,0..20]]; Use Q[x[1..2,0..20]], Ord(DA.DiffTO("Lex")); F:=x[1,2]^3x[2,2]^2 + x[1,1]^3x[2,2]^2 + 1/4x[1,2]; DA.InitialOfDer(F, x[1,2]); ------------------------------- x[2,2]^2 -------------------------------