Difference between revisions of "ApCoCoA1:DA.NthDerivation"
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DA.NthDerivation
Computes the Nth derivation of a differential polynomial.
Syntax
DA.NthDerivation(F:POLY, N:INT):POLY
Description
Computes the Nth derivation of the differential polynomial F. If the order of the result would exceed the given maximum order as implied by the current ring, an error is thrown.
@param F A differential polynomial.
@param N An integer.
@return The Nth derivation of F.
Example
Use QQ[x[1..2,0..20]]; F:=x[1,2]^2*x[1,1]x[2,4]^3; DA.NthDerivation(F, 2);  5x[1,2]^2x[1,3] + 2x[1,1]x[1,3]^2 + 2x[1,1]x[1,2]x[1,4]  6x[2,4]x[2,5]^2  3x[2,4]^2x[2,6] 
Example
Use Q[x[1..2,0..20]]; F:=x[1,2]^2*x[1,1]x[2,4]^3; DA.NthDerivation(F, 20);  ERROR: Maximum order is exceeded. CONTEXT: Error(<quotes>Maximum order is exceeded.</quotes>) 