Overview
In algebra, the Binet–Cauchy identity, named after Jacques Philippe Marie Binet and Augustin-Louis Cauchy, states that
for every choice of real or complex numbers .
Setting ai = ci and bj = dj, it gives Lagrange's identity, which is a stronger version of the Cauchy–Schwarz inequality for the Euclidean space . The Binet-Cauchy identity is a special case of the Cauchy–Binet formula for matrix determinants.
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