Van der Corput lemma (harmonic analysis)
= Van der Corput lemma (harmonic analysis)
{wiki=Van_der_Corput_lemma_(harmonic_analysis)}
The Van der Corput lemma is a result in harmonic analysis that provides a way to estimate oscillatory integrals, especially integrals of the form: \\\[ \\int e^\{i \\phi(t)\} f(t) \\, dt \\\] where \\( \\phi(t) \\) is a smooth function, and \\( f(t) \\) is usually a function that is well-behaved (often in \\( L^1 \\) space).