### 5.29.2 Polynomials of several variables: %%%{ %%%}

A polynomial of several variables is represented

- by a symbolic expression
- or by a dense recursive 1-d representation like above
- or by a sum of monomials with non-zero coefficients (distributed sparse representation).
  A monomial with several variables is represented by a coefficient and a list of integers (interpreted as powers of a variable list). The delimiters for monomials are %%%{ and %%%}, for example 3x2y is represented by %%%{3,[2,1]%%%} with respect to the variable list [x,y]).