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This paper is purely expository. We present short elementary proofs of * the Gauss Theorem on constructibility of regular polygons; * the existence of a cubic equation unsolvable in real radicals; * the existence of a quintic equation…

General Mathematics · Mathematics 2026-01-08 A. Skopenkov

We retrace Davenport's solution to Wahba's classic problem of aligning two pointclouds using the formalism of Geometric Algebra (GA). GA proves to be a natural backdrop for this problem involving three-dimensional rotations due to the…

Robotics · Computer Science 2021-03-08 Timothy D Barfoot

The Umehara algebra is studied with motivation on the problem of the non-existence of common complex submanifolds. In this paper, we prove some new results in Umehara algebra and obtain some applications. In particular, if a complex…

Complex Variables · Mathematics 2022-11-03 Xu Zhang , Donghai Ji

We provide a list of (mainly unsolved) problems in ordered and orderable groups. These were originally compiled 10 years ago by the last two authors. New problems have been added to the list. Progress on some of these is noted and…

Group Theory · Mathematics 2009-06-16 V. V. Bludov , A. M. W. Glass , V. M. Kopytov , N. Ya. Medvedev

This paper is purely expositional. The statement of the Abel-Ruffini theorem on unsolvability of equations using radicals is simple and well-known. We sketch an elementary proof of this theorem. We do not use the terms 'field extension',…

History and Overview · Mathematics 2013-05-22 A. Skopenkov

It is well known that several classical geometry problems (e.g., angle trisection) are unsolvable by compass and straightedge constructions. But what kind of object is proven to be non-existing by usual arguments? These arguments refer to…

History and Overview · Mathematics 2018-06-01 Vladimir Uspenskiy , Alexander Shen

Euler's solution in 1734 of the Basel problem, which asks for a closed form expression for the sum of the reciprocals of all perfect squares, is one of the most celebrated results of mathematical analysis. In the modern era, numerous proofs…

Classical Analysis and ODEs · Mathematics 2023-12-12 F. L. Freitas

Our result contains as special cases the Frobenius theorem (1895) on the number of solutions to the equation $x^n=1$ in a group, the Solomon theorem (1969) on the number of solutions in a group to a system of equations having fewer…

Group Theory · Mathematics 2019-12-04 Elena K. Brusyanskaya , Anton A. Klyachko , Andrey V. Vasil'ev

The mathematical aspects of the popular logic game Sudoku incorporate a significant number of the group theory concepts. In this note, we describe all symmetric transformations of the Sudoku grid. We do not intend to obtain a new strategy…

Group Theory · Mathematics 2011-06-07 Vasiliy Osipov

In this report we consider the set of the 16 possible convex tangrams that can be composed with the 7 so-called "Sei Shonagon Chie no Ita" (or Japanese) tans, see [10]. The set of these Japanese tans is slightly different from the…

History and Overview · Mathematics 2018-12-04 T. G. J. Beelen , T. Verhoeff

In this preprint we present an outline of the multidimensional version of topological Galois theory. The theory studies topological obstruction to solvability of equations "in finite terms" (i.e. to their solvability by radicals, by…

Algebraic Geometry · Mathematics 2019-04-17 Askold Khovanskii

Recently, the problem of the infinite spherical well was solved by the group-theoretical method to resolve all the peculiarities in the currently accepted solution [DOI: 10.13140/RG.2.2.18172.44162 (Researchgate, 2017)]. With a view to…

Quantum Physics · Physics 2017-11-10 Young-Sea Huang , Chun-Hsien Wu , Kung-Te Wu , Tzuu-Kang Chyi , Huitzu Tu

A criterion for the existence of a plane model with two non-smooth Galois points for algebraic curves is presented, which is a generalization of Fukasawa's criterion for two smooth Galois points. Owing to this generalized criterion,…

Algebraic Geometry · Mathematics 2020-10-06 Kazuki Higashine

This is a collection of open problems in group theory proposed by hundreds of mathematicians from all over the world. It has been published every 2--4 years since 1965. This is the 21st edition, which contains 150 new problems and a number…

Group Theory · Mathematics 2026-05-13 E. I. Khukhro , V. D. Mazurov

The goal of this paper is to develop a group-theoretic algorithm, to reconstruct a number field (together with its maximal m-step solvable ex- tension for some positive integer m \geq 3) from the maximal m+9-step solv- able quotient of its…

Number Theory · Mathematics 2025-11-10 Yu Mao , Mohamed Saidi

The development of computational techniques in the last decade has made possible to attack some classical problems of algebraic geometry. In this survey, we briefly describe some open problems related to algebraic curves which can be…

Commutative Algebra · Mathematics 2007-05-23 Tanush Shaska

In this paper, we give a survey of a geometrical theory of Jacobi forms of higher degree. And we present some geometric results and discuss some geometric problems to be investigated in the future.

Number Theory · Mathematics 2007-05-23 Jae-Hyun Yang

Solving a system of polynomial equations is a ubiquitous problem in the applications of mathematics. Until recently, it has been hopeless to find explicit solutions to such systems, and mathematics has instead developed deep and powerful…

Algebraic Geometry · Mathematics 2007-05-23 Frank Sottile

In 1943 from September to December Kiyoshi Oka wrote a series of papers numbered from VII to XI, as the research reports to Teiji Takagi (then, Professor of Tokyo Imperial University), in which he solved affirmatively the so-called Levi…

Complex Variables · Mathematics 2022-04-29 Junjiro Noguchi

Flat-foldability problem of origami is the problem to determine whether a given crease pattern drawn on a piece of paper is possible to fold without any penetration or intrusion of a polygon into any connections among them. It is known from…

Disordered Systems and Neural Networks · Physics 2025-06-17 Chihiro Nakajima