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

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S schuster (talk | contribs) m (ApCoCoA:Diffalg.InitialOfDer moved to ApCoCoA:DA.InitialOfDer: To comply with style principles.) |
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DA.InitialOfDer returns the polynomial leading coefficient of polynomial F regarded as polynomial in the derivative X. | DA.InitialOfDer returns the polynomial leading coefficient of polynomial F regarded as polynomial in the derivative X. | ||

<itemize> | <itemize> | ||

− | <item>@param F A differential polynomial.</item> | + | <item>@param <em>F</em> A differential polynomial.</item> |

− | <item>@param X A indeterminate.</item> | + | <item>@param <em>X</em> A indeterminate.</item> |

<item>@return Initial of F wrt. X.</item> | <item>@return Initial of F wrt. X.</item> | ||

</itemize> | </itemize> | ||

Line 29: | Line 29: | ||

<see>DA.Initial</see> | <see>DA.Initial</see> | ||

<see>DA.DiffTO</see> | <see>DA.DiffTO</see> | ||

+ | |||

<key>InitialOfDer</key> | <key>InitialOfDer</key> | ||

<key>DA.InitialOfDer</key> | <key>DA.InitialOfDer</key> |

## Revision as of 11:05, 23 April 2009

## 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 -------------------------------