Converting to a symbolic polynomial

The r2e or poly2symb command converts lists into symbolic polynomials.

For one-variable polynomials, r2e takes one mandatory argument and one optional argument:
- L, a list of coefficients of a polynomial (in decreasing order),
- x, a symbolic variable name (by default x).
r2e(L ⟨,x⟩) returns the corresponding polynomial with the given variable.
For sparse multivariate polynomials, r2e takes two arguments:
- S, a sum of monomials of the form %%%{coeff,[n1,…,nk]%%%}.
- vars, a vector of symbolic variables.
r2e(S ⟨,vars ⟩) returns the corresponding polynomial as an expression with the given variables

r2e([1,0,-1],x)

or:

r2e([1,0,-1])

or:

poly2symb([1,0,-1],x)

x x−1

poly2symb(%%%{1,[2]%%%}+%%%{-1,[0]%%%},[x])

or:

r2e(%%%{1,[2]%%%}+%%%{-1,[0]%%%},[x])

x²−1

r2e(%%%{1,[2,0]%%%}+%%%{-1,[1,1]%%%}+%%%{2,[0,1]%%%},[x,y])

or:

poly2symb(%%%{1,[2,0]%%%}+%%%{-1,[1,1]%%%}+%%%{2,[0,1]%%%},[x,y])

x²−x y+2 y