What is "homogeneous polynomial"

n. (context mathematics English) a polynomial such that the sum of the exponents of the variables is the same for every term.

In mathematics, a homogeneous polynomial is a polynomial whose nonzero terms all have the same degree. For example, x + 2xy + 9xy is a homogeneous polynomial of degree 5, in two variables; the sum of the exponents in each term is always 5. The polynomial x + 3xy + z is not homogeneous, because the sum of exponents does not match from term to term. A polynomial is homogeneous if and only if it defines a homogeneous function. An algebraic form, or simply form, is a function defined by a homogeneous polynomial. A binary form is a form in two variables. A form is also a function defined on a vector space, which may be expressed as a homogeneous function of the coordinates over any basis.

A polynomial of degree 0 is always homogeneous; it is simply an element of the field or ring of the coefficients, usually called a constant or a scalar. A form of degree 1 is a linear form. A form of degree 2 is a quadratic form. In geometry, the Euclidean distance is the square root of a quadratic form.

Homogeneous polynomials are ubiquitous in mathematics and physics. They play a fundamental role in algebraic geometry, as a projective algebraic variety is defined as the set of the common zeros of a set of homogeneous polynomials.