inverse(FormalSeries) -- multiplicative inverse of formal series

Synopsis

• Function: inverse

• Usage:

  inverse(s)

• Inputs:
  • s, an instance of the type FormalSeries
• Outputs:
  • an instance of the type FormalSeries, the multiplicative inverse of the formal series s

Description

i1 : R=ZZ[x,y]

o1 = R

o1 : PolynomialRing

i2 : s = series(2*x^2*y+x*y+x^2+x+y+1,3)

                    2     2
o2 = FormalSeries{2x y + x  + x*y + x + y + 1, 3}

o2 : FormalSeries

i3 : inverse(s)

                   3    2       2    3          2
o3 = FormalSeries{x  - x y - x*y  - y  + x*y + y  - x - y + 1, 3}

o3 : FormalSeries

Caveat