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diff -- differentiate or take difference

Synopsis

Description

This function has two different uses. The most common use is for differentiation: differentiate the second input by the first.

The second use, less common but sometimes useful, is to compute the difference polynomial of a Hilbert polynomial.

The arguments can also be ring elements or vectors.
i1 : R = ZZ[x,y,z]

o1 = R

o1 : PolynomialRing
i2 : f = vars R ** vars R

o2 = | x2 xy xz xy y2 yz xz yz z2 |

             1      9
o2 : Matrix R  <-- R
i3 : diff(transpose vars R, f)

o3 = {1} | 2x y z y 0  0 z 0 0  |
     {1} | 0  x 0 x 2y z 0 z 0  |
     {1} | 0  0 x 0 0  y x y 2z |

             3      9
o3 : Matrix R  <-- R
i4 : diff(x, f)

o4 = | 2x y z y 0 0 z 0 0 |

             1      9
o4 : Matrix R  <-- R
i5 : diff(y, f)

o5 = | 0 x 0 x 2y z 0 z 0 |

             1      9
o5 : Matrix R  <-- R
i6 : diff(z, f)

o6 = | 0 0 x 0 0 y x y 2z |

             1      9
o6 : Matrix R  <-- R

See also

Ways to use diff :

For the programmer

The object diff is a method function.

Menu

differentiation

difference operator for Hilbert polynomials