 Suppose that formula_1 is a probability measure on the unit circle in the complex plane, whose support is not finite.The orthogonal polynomials associated to formula_1 are the polynomials formula_3 with leading term formula_4 that are orthogonal with respect to the measure formula_1.Szegő's recurrence states that

where
is the polynomial with its coefficients reversed and complex conjugated, and where the Verblunsky coefficients formula_9 are complex numbers with absolute values less than 1.