New posts in quadratic-forms

Representing a number as a sum of at most $k$ squares

elementary-number-theory analytic-number-theory modular-forms quadratic-forms

Solve $ \binom{a}{2} + \binom{b}{2} = \binom{c}{2} $ with $a,b,c \in \mathbb{Z}$

number-theory diophantine-equations quadratic-forms pythagorean-triples

On products of ternary quadratic forms $\prod_{i=1}^3 (ax_i^2+by_i^2+cz_i^2) = ax_0^2+by_0^2+cz_0^2$

number-theory algebraic-number-theory diophantine-equations quadratic-forms

Hessian matrix of a quadratic form

matrices multivariable-calculus derivatives quadratic-forms

Surface described by the equation $-3y^2 - 4xy + 2xz + 4yz - 2x - 2z + 1 = 0$

linear-algebra geometry surfaces quadratic-forms

Existence of solutions to diophantine quadratic form

number-theory diophantine-equations quadratic-forms

What conditions would make a system of two quadratic equations have one real solution?

quadratics graphing-functions quadratic-forms

How find this matrix $A=(\sqrt{i^2+j^2})$ eigenvalue

linear-algebra matrices quadratic-forms

Is it true that the whole space is the direct sum of a subspace and its orthogonal space?

linear-algebra geometry quadratic-forms bilinear-form symplectic-linear-algebra

Minimum of a quadratic form

linear-algebra matrices optimization eigenvalues-eigenvectors quadratic-forms

Gradient of $\sum_{i,j}^n A_{ij}x_i^TB^iC{B^j}^Tx_j$

matrices multivariable-calculus derivatives quadratic-forms scalar-fields

Every nondegenerate quadratic form defined on a two dimensional space over a finite field is universal.

quadratic-forms

Minimize a Quadratic Cost Function on the Unit Simplex

optimization convex-optimization nonlinear-optimization quadratic-forms quadratic-programming

What integers can be represented by the quadratic form $4x^2 - 3y^2 - z^2$?

number-theory diophantine-equations quadratic-forms

Determining if a quadratic polynomial is always positive

calculus inequality quadratics quadratic-forms

Solution to a quadratic form

linear-algebra conic-sections quadratic-forms

Elementary properties of integral binary quadratic forms

elementary-number-theory quadratic-forms

If $x^{T}A^{T}Ax = x^Tx$ holds for every $x$, then $A^{T} A = I_n$ [closed]

matrices quadratic-forms

Showing $u^T M u \geq v^TMv$ when $M$ is symmetric PD and $u,v$ are $0-1$ vectors

matrices eigenvalues-eigenvectors quadratic-forms

Using Lagrange's diagonalization on degenerate linear forms

linear-algebra quadratic-forms bilinear-form