All monomials, polynomials and rational functions are elementary. The most common polynomial basis is the monomial basis consisting of all monomials. In elementary algebra, a trinomial is a polynomial consisting of three terms or monomials. A binomial is a polynomial which is the sum of two monomials. It is the simplest kind of polynomial after the monomials. Notation for monomials is constantly required in fields like partial differential equations. This binomial coefficient is the number of "n"-variable monomials of degree "k". Simple examples of invariant theory come from computing the invariant monomials from a group action. It is a generalization of Horner's method for evaluating a linear combination of monomials. The entries of the matrix depend on the product of the indexing monomials only (cf. A posynomial is any sum of monomials. Often one may think of the space as spanned by all suitable field monomials. Notice that the monomials formula 37 generate the ring formula 38. Thus, there are three monomials in "B". Monomials in "n" variables define homogeneous functions .