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In this paper we show that a split central simple algebra with quadratic pair which decomposes into a tensor product of quaternion algebras with involution and a quaternion algebra with quadratic pair is adjoint to a quadratic Pfister form.…

Rings and Algebras · Mathematics 2016-04-15 Karim Johannes Becher , Andrew Dolphin

We study quartic double fivefolds from the perspective of Fano manifolds of Calabi-Yau type and that of exceptional quaternionic representations. We first prove that the generic quartic double fivefold can be represented, in a finite number…

Algebraic Geometry · Mathematics 2017-10-13 Roland Abuaf

In this paper we generalize the result of Fouvry and Iwaniec dealing with prime values of the quadratic form $x^2 + y^2$ with one input restricted to a thin subset of the integers. We prove the same result with an arbitrary primitive…

Number Theory · Mathematics 2020-05-27 Peter Cho-Ho Lam , Damaris Schindler , Stanley Yao Xiao

For all positive integers $k$ and $N$ we prove that there are infinitely many totally real multiquadratic fields $K$ of degree $2^k$ over $\mathbb Q$ such that each universal quadratic form over $K$ has at least $N$ variables.

Number Theory · Mathematics 2019-01-24 Vítězslav Kala , Josef Svoboda

For a (positive definite and integral) quadratic form $f$, a quadratic form is said to be {\it an isolation of $f$ from its proper subforms} if it represents all proper subforms of $f$, but not $f$ itself. It was proved that the minimal…

Number Theory · Mathematics 2023-08-10 Jangwon Ju , Daejun Kim , Kyoungmin Kim , Mingyu Kim , Byeong-Kweon Oh

We show that the iterated images of a Jacobian pair stabilize; that is, the k-th iterates of a polynomial map of complex two-space to itself with a nonzero constant Jacobian determinant all have the same image for sufficiently large k. More…

Algebraic Geometry · Mathematics 2010-01-24 Ronen Peretz , Nguyen Van Chau , Carlos Gutierrez , L. Andrew Campbell

This paper addresses two fundamental problems posed by Qi regarding the sufficiency of eigenvalues for the classification of symmetric tensors in the two-dimensional setting. For $2\times2\times2$ and $2\times2\times2\times2$ complex…

Rings and Algebras · Mathematics 2025-12-22 Lishan Fang , Hua-Lin Huang

We consider quadrangles of perimeter $2$ in the plane with marked directed edge. To such quadrangle $Q$ a two-dimensional plane $\Pi\in\mathbb{R}^4$ with orthonormal base is corresponded. Orthogonal plane $\Pi^\bot$ defines a plane…

Metric Geometry · Mathematics 2019-11-22 Irina Busjatskaja , Yury Kochetkov

Given a newform f, we extend Howard's results on the variation of Heegner points in the Hida family of f to a general quaternionic setting. More precisely, we build big Heegner points and big Heegner classes in terms of compatible families…

Number Theory · Mathematics 2010-10-19 M. Longo , S. Vigni

For any pair of orientable closed hyperbolic $3$--manifolds, this paper shows that any isomorphism between the profinite completions of their fundamental groups witnesses a bijective correspondence between the Zariski dense…

Geometric Topology · Mathematics 2023-08-22 Yi Liu

We use methods of the general theory of congruence and *congruence for complex matrices--regularization and cosquares-to determine a unitary congruence canonical form (respectively, a unitary *congruence canonical form) for complex matrices…

Representation Theory · Mathematics 2012-12-14 Roger A. Horn , Vladimir V. Sergeichuk

Let $\psi$ and $F$ be positive definite forms with integral coefficients of equal degree. Using the circle method, we establish an asymptotic formula for the number of identical representations of $\psi$ by $F$, provided $\psi$ is…

Number Theory · Mathematics 2015-08-17 Julia Brandes

A recent conjecture of the author and Teng Fang states that there are only finitely many finite simple groups with no cubic graphical regular representation. In this paper, we make a crucial progress towards this conjecture by giving an…

Combinatorics · Mathematics 2019-06-11 Binzhou Xia

Welschinger invariants enumerate real nodal rational curves in the plane or in another real rational surface. We analyze the existence of similar enumerative invariants that count real rational plane curves having prescribed non-nodal…

Algebraic Geometry · Mathematics 2024-06-25 Eugenii Shustin

Commutative hypercomplex algebras offer significant advantages over traditional quaternions due to their compatibility with linear algebra techniques and efficient computational implementation, which is crucial for broad applicability. This…

We consider the question of determining whether two binary cubic forms over an arbitrary field $K$ whose characteristic is not $2$ or $3$ are equivalent under the actions of either GL$(2,K)$ or SL$(2,K)$, deriving two necessary and…

Number Theory · Mathematics 2025-12-03 J E Cremona

The problem of minimizing a (nonconvex) quadratic form over the unit simplex, referred to as a standard quadratic program, admits an exact convex conic formulation over the computationally intractable cone of completely positive matrices.…

Optimization and Control · Mathematics 2020-03-02 Y. Gorkem Gokmen , E. Alper Yildirim

We study the minimal number of variables required by a totally positive definite diagonal universal quadratic form over a real quadratic field $\mathbb Q(\sqrt D)$ and obtain lower and upper bounds for it in terms of certain sums of…

Number Theory · Mathematics 2018-07-05 Valentin Blomer , Vítězslav Kala

We determine the border rank of each power of any quadratic form in three variables. Since the problem for rank $1$ and rank $2$ quadratic forms can be reduced to determining the rank of powers of binary forms, we primarily focus on…

Algebraic Geometry · Mathematics 2023-08-03 Cosimo Flavi

Let ${\mathscr A}(D)$ be an algebra of functions continuous in the disk $D=\{z\in{\mathbb C}\,|\,\,\,|z|\leqslant 1\}$ and {\it holomorphic} into $D$. The well-known fact is that the set ${\mathscr M}$ of its characters (homomorphisms…

Functional Analysis · Mathematics 2017-10-13 Mikhail I. Belishev , Aleksei F. Vakulenko