Let V {\displaystyle {}V} be a finite-dimensional C {\displaystyle {}\mathbb {C} } -vector space, endowed with a sesquilinear form ⟨ − , − ⟩ {\displaystyle {}\left\langle -,-\right\rangle } . Let v 1 , … , v n {\displaystyle {}v_{1},\ldots ,v_{n}} be a basis of V {\displaystyle {}V} . The n × n {\displaystyle {}n\times n} -matrix
is called the Gram matrix of ⟨ − , − ⟩ {\displaystyle {}\left\langle -,-\right\rangle } with respect to this basis.