How do I prove that given Q indefinite quadratic form it has at least an isotropic vector?
I think I should use the signature (Sylvester's Theorem) and Fuorier's Theorem?
Like I know that sgn(Q)=(p, r-p) [0<p<r] but how do I prove that r<n (with n equal to the dimension of the ambient space)
Apologies for my poor english.
I think I should use the signature (Sylvester's Theorem) and Fuorier's Theorem?
Like I know that sgn(Q)=(p, r-p) [0<p<r] but how do I prove that r<n (with n equal to the dimension of the ambient space)
Apologies for my poor english.