Sophus Lie Research Articles

Felix Klein and Sophus Lie on quartic surfaces in line geometry

Felix Klein and Sophus Lie on quartic surfaces in line geometry

Symmetry and symmetric transformations in mathematical imaging

The article delves into the intricate relationship between symmetry and mathematical imaging, spanning various mathematical disciplines. Symmetry, a concept deeply ingrained in mathematics, manifests in art, nature, and physics, providing a powerful tool for understanding complex structures. The paper explores three types of symmetriesreflection, rotational, and translationalexemplified through concrete mathematical expressions. Evariste Galoiss Group Theory emerges as a pivotal tool, providing a formal framework to understand and classify symmetric operations, particularly in the roots of polynomial equations. Galois theory, a cornerstone of modern algebra, connects symmetries, permutations, and solvability of equations. Group theory finds practical applications in cryptography, physics, and coding theory. Sophus Lie extends group theory to continuous spaces with Lie Group Theory, offering a powerful framework for studying continuous symmetries. Lie groups find applications in robotics and control theory, streamlining the representation of transformations. Benoit Mandelbrots fractal geometry, introduced in the late 20th century, provides a mathematical framework for understanding complex, self-similar shapes. The applications of fractal geometry range from computer graphics to financial modeling. Symmetrys practical applications extend to data visualization and cryptography. The article concludes by emphasizing symmetrys foundational role in physics, chemistry, computer graphics, and beyond. A deeper understanding of symmetry not only enriches perspectives across scientific disciplines but also fosters interdisciplinary collaborations, unveiling hidden order and structure in the natural and designed world. The exploration of symmetry promises ongoing discoveries at the intersection of mathematics and diverse fields of study.

On Uniqueness of Submaximally Symmetric Vector Ordinary Differential Equations of C-Class

The fundamental invariants for vector ODEs of order $\ge 3$ considered up to point transformations consist of generalized Wilczynski invariants and C-class invariants. An ODE of C-class is characterized by the vanishing of the former. For any fixed C-class invariant ${\mathcal U}$, we give a local (point) classification for all submaximally symmetric ODEs of C-class with ${\mathcal U} \not \equiv 0$ and all remaining C-class invariants vanishing identically. Our results yield generalizations of a well-known classical result for scalar ODEs due to Sophus Lie. Fundamental invariants correspond to the harmonic curvature of the associated Cartan geometry. A key new ingredient underlying our classification results is an advance concerning the harmonic theory associated with the structure of vector ODEs of C-class. Namely, for each irreducible C-class module, we provide an explicit identification of a lowest weight vector as a harmonic 2-cochain.

Lie group classification of the nonlinear transmission line model and exact traveling wave solutions

A nonlinear transmission line (NLTL) model is very essential tools in understanding of propagation of electrical solitons which can propagate in the form of voltage waves in nonlinear dispersive media. These models are often formulated using nonlinear partial differential equations. One of the basic tools available to study these equations are numerical methods such as finite difference method, finite element method, etc, have been developed for nonlinear partial differential equations. These methods require a great amount of time and memory due to the discretization and usually the effect of round-off error causes loss of accuracy in the results. So in this paper, we use one of the most famous analytical methods the Lie group analysis due to Sophus Lie. One of the advantages of this approach is that requires only algebraic calculations. The main aim of this study is to explore the nonlinear transmission line model with arbitrary capacitor's voltage dependence, through the use of Lie group classification, we show that the specifying form of arbitrary capacitor's voltage are power law nonlinearity, exponential law nonlinearity and constant capacitance. The exact solutions and similarity reductions generated from the symmetries are also provided. Furthermore, translational symmetries were utilized to find a family of traveling wave solutions via the \(\tanh\)-method of the governing nonlinear problem.

3-dimensional Levi-Civita metrics with projective vector fields

Projective vector fields are the infinitesimal transformations whose local flow preserves geodesics up to reparametrisation. In 1882, Sophus Lie posed the problem of describing 2-dimensional metrics admitting a non-trivial projective vector field, which was solved in recent years. In the present paper, we solve the analog of Lie's problem in dimension 3, for Riemannian metrics and, more generally, for Levi-Civita metrics of arbitrary signature.

Unlawful Calculations: A Look Into Lie’s Notebook

Summary Sophus Lie was arrested in 1870 because of his mathematics notebook. In his notes, Lie used geometry to solve differential equations by identifying transformations that leave solutions unchanged. These transformations suggested a change of variable that made the differential equations easier to solve. Lie groups were born in those notes. This article reveals Lie’s unlawful methods that could lead to a life of crime.

Symplectic realizations of holomorphic Poisson manifolds

Symplectic realization is a longstanding problem which can be traced back to Sophus Lie. In this paper, we present an explicit solution to this problem for an arbitrary holomorphic Poisson manifold. More precisely, for any holomorphic Poisson manifold $(X, \pi)$, we prove that there exists a holomorphic symplectic structure in a neighborhood $Y$ of the zero section of $T^*X$ such that the projection map is a symplectic realization of the given Poisson manifold, and moreover the zero section is a holomorphic Lagrangian submanifold. We describe an explicit construction for such a new holomorphic symplectic structure on $Y \subseteq T^*X$.

Projective Properties of Divergence-Free Symmetric Tensors, and New Dispersive Estimates in Gas Dynamics

The class of Divergence-free symmetric tensors is ubiquitous in Continuum Mechanics. We show its invariance under projective transformations of the independent variables. This action, which preserves the positiveness, extends Sophus Lie’s group analysis of Newtonian dynamics. When applied to models of gas dynamics—such as Euler system or Boltzmann equation,—in combination with Compensated Integrability, this yields new dispersive estimates. The most accurate one is obtained for mono-atomic gases. Then the space-time integral of \(t\rho ^\frac{1}{d} p\) is bounded in terms of the total mass and moment of inertia alone.

From Photon to Oganesson: Lie Algebra Realization of the Standard Model Extending over the Periodic Table

As reported in a series of previous PIRT conferences, a direct SU(3) structural realization of the Standard Model has been developed based upon Marius Sophus Lie’s original Norwegian Ph.D. thesis Over en Classe Geometriske Transformationer from 1871 (and thus due for a most deserved 150-year anniversary). It elucidates how “the theory of main tangential curves can be brought back to that of rounded curves”, anticipating a coherent linear representation of the elementary particles instead of the rotational chosen since they were considered point-like and amorphous when they many years later entered the stage. Under these premises the Standard Model has built a magnificent, undoubtedly true but congested multi-particle system whereas the Lie continuous transformation element, the partial derivative ’straight line of length equal to zero’ outlines an isotropic vector matrix lattice of crystallographic Killing root space diagram A3 form which from the Nucleon and inwards can backtrack the Standard Model geometrically, as well as continue outward iterating to a space-filling solid state R3×SO(3) wave-packet complex tessellating the whole periodic table with electron shells and subshells, isotope spectrum, neutron captures, radiative channels, oxidation states, molecular binding sites etc. in successive layers also including the Lanthanides in the sixth period and the Actinides in the seventh, in which now the concluding Oganesson has been reached in perfectly well-built saturated noble gas shape and condition.

On the 100th Anniversary of the Full Member of Russian Academy Of Sciences L.V. Ovsyannikov and the 80th Anniversary of His Follower, Professor N.H. Ibragimov

Two dates coincided in 2019: the centenary of the full member of Russian Academy of Sciences Lev Vasilievich Ovsyannikov (April 22, 1919 -- May 23, 2014) and the eightieth anniversary of his follower, professor Nail Hairullovich Ibragimov (January 18, 1939 -- November 04, 2018). Through the efforts of them and their numerous students and followers, Sophus Lie's theory of local transformation groups was revived and received promising development.

On the Eight Dimensional Point Symmetries of Second Order Linear O.D.E's

The purpose of this paper is to review Sophus Lie's methods for differential equations, shedding light on the Lie point symmetries of generic linear second order ordinary differential equations (O.D.E's). As a matter of necessity in the overall review, there are important contrasts highlighted in derivations of the infinitesimal generators, with and without the prior application of point transformations.

On the Eight Dimensional Point Symmetries of Second Order Linear O.D.E's

The purpose of this paper is to review Sophus Lie's methods for differential equations, shedding light on the Lie point symmetries of generic linear second order ordinary differential equations (O.D.E's). As a matter of necessity in the overall review, there are important contrasts highlighted in derivations of the infinitesimal generators, with and without the prior application of point transformations.

A History of Group Theory through the Lives of Group Theorists: Sophus Lie - Part 1

A History of Group Theory through the Lives of Group Theorists: Sophus Lie - Part 1

ТОЧНІ РОЗВ’ЯЗКИ НЕЛІНІЙНОГО (1+2)-ВИМІРНОГО РІВНЯННЯ РЕАКЦІЇ-КОНВЕКЦІЇ-ДИФУЗІЇ

Предметом вивчення в статті є застосування ліївського методу до побудови інваріантних анзаців, редукції та знаходження точних розв’язків (1+2)-вимірного рівняння реакції-конвекції-дифузії. Мета - здійснити побудову точних розв’язків (1+2)-вимірного рівняння реакції-конвекції-дифузії на основі використання симетричних властивостей цього рівняння. Задача − використати ліївську симетрію рівняння (1+2)-вимірного рівняння реакції-конвекціїдифузії для побудови інваріантних анзаців, редукції та знаходження його точних розв’язків. Для реалізації цієї задачі використано метод Софуса Лі, в основі його лежить принцип симетрії. Згідно з методом С. Лі диференціальні рівняння з частинними похідними, які володіють класичною лііївською симетрією, можна редукувати до звичайних диференціальних рівнянь за допомогою спеціальних підстановок(анзаців). Розв’язавши редуковані рівняння, можна побудувати точні розв’язки вихідного диференціального рівняння з частинними похідними. Висновки: використано симетрійні властивості (1+2)-вимірного рівняння реакції-конвекції-дифузії для побудови інваріантних анзаців, редукції та знаходження його точних розв’язків.

INVARIANTS OF GENERALIZED RAPOPORT-LEAS EQUATIONS

For the generalized Rapoport-Leas equations, algebra of differential invariants is constructed with respect to point transformations, that is, transformations of independent and dependent variables. The finding of a general transformation of this type reduces to solving an extremely complicated functional equation. Therefore, following the approach of Sophus Lie, we restrict ourselves to the search for infinitesimal transformations which are generated by translations along the trajectories of vector fields. The problem of finding these vector fields reduces to the redefined system decision of linear differential equations with respect to their coefficients. The Rapoport-Leas equations arise in the study of nonlinear filtration processes in porous media, as well as in other areas of natural science: for example, these equations describe various physical phenomena: two-phase filtration in a porous medium, filtration of a polytropic gas, and propagation of heat at nuclear explosion. They are vital topic for research: in recent works of Bibikov, Lychagin, and others, the analysis of the symmetries of the generalized Rapoport-Leas equations has been carried out; finite-dimensional dynamics and conditions of attractors existence have been found. Since the generalized RapoportLeas equations are nonlinear partial differential equations of the second order with two independent variables; the methods of the geometric theory of differential equations are used to study them in this paper. According to this theory differential equations generate subvarieties in the space of jets. This makes it possible to use the apparatus of modern differential geometry to study differential equations. We introduce the concept of admissible transformations, that is, replacements of variables that do not derive equations outside the class of the Rapoport-Leas equations. Such transformations form a Lie group. For this Lie group there are differential invariants that separate its regular orbits, which allow us to classify the generalized Rapoport-Leas equations.

Analytic Solutions of Nonlinear Partial Differential Equations by the Power Index Method

An updated Power Index Method is presented for nonlinear differential equations (NLPDEs) with the aim of reducing them to solutions by algebraic equations. The Lie symmetry, translation invariance of independent variables, allows for traveling waves. In addition discrete symmetries, reflection, or 180 ° rotation symmetry, are possible. The method tests whether certain hyperbolic or Jacobian elliptic functions are analytic solutions. The method consists of eight steps. The first six steps are quickly applied; conditions for algebraic equations are more complicated. A few exceptions to the Power Index Method are discussed. The method realizes an aim of Sophus Lie to find analytic solutions of nonlinear differential equations.

Articulating Space in Terms of Transformation Groups: Helmholtz and Cassirer

Hermann von Helmholtz’s geometrical papers (1868–1878) have been typically deemed to provide an implicitly group-theoretical analysis of space, as articulated later by Felix Klein, Sophus Lie, and Henri Poincaré. However, there is less agreement as to what properties exactly in such a view would pertain to space, as opposed to abstract mathematical structures, on the one hand, and empirical contents, on the other. According to Moritz Schlick, the puzzle can be resolved only by clearly distinguishing the empirical qualities of spatial perception from those describable in terms of axiomatic geometry. This paper offers a partial defense of the group-theoretical reading of Helmholtz along the lines of Ernst Cassirer in the fourth volume of The Problem of Knowledge of 1940. In order to avoid the problem raised by Schlick, Cassirer relied on a Kantian view of space not so much as an object of geometry, but as a precondition for the possibility of measurement. Although the concept of group does not provide a description of space, the modern way to articulate the concept of space in terms of transformation groups reveals something about the structure and the transformation of spatial concepts in mathematical and natural sciences.

Symmetry Reduction of Ordinary Differential Equations Using Moving Frames

The symmetry reduction algorithm for ordinary differential equations due to Sophus Lie is revisited using the method of equivariant moving frames. Using the recurrence formulas provided by the theory of equivariant moving frames, computations are performed symbolically without relying on the coordinate expressions for the canonical variables and the differential invariants occurring in Lie’s original procedure.

The origins of seminar Sophus Lie—a keynote address to the 50th session of Seminar Sophus Lie

The origins of seminar Sophus Lie—a keynote address to the 50th session of Seminar Sophus Lie

Analytic functions in a unit ball of bounded $\mathbf{L}$-index: asymptotic and local properties

Historian Herbert Mehrtens sought to portray the history of turn-of-the-century mathematics as a struggle of modern vs countermodern, led respectively by David Hilbert and Felix Klein. Some of Mehrtens' conclusions have been picked up by both historians (Jeremy Gray) and mathematicians (Frank Quinn). We argue that Klein and Hilbert, both at Goettingen, were not adversaries but rather modernist allies in a bid to broaden the scope of mathematics beyond a narrow focus on arithmetized analysis as practiced by the Berlin school. Klein's Goettingen lecture and other texts shed light on Klein's modernism. Hilbert's views on intuition are closer to Klein's views than Mehrtens is willing to allow. Klein and Hilbert were equally interested in the axiomatisation of physics. Among Klein's credits is helping launch the career of Abraham Fraenkel, and advancing the careers of Sophus Lie, Emmy Noether, and Ernst Zermelo, all four surely of impeccable modernist credentials. Mehrtens' unsourced claim that Hilbert was interested in production rather than meaning appears to stem from Mehrtens' marxist leanings. Mehrtens' claim that [the future SS-Brigadefuehrer] "Theodor Vahlen ... cited Klein's racist distinctions within mathematics, and sharpened them into open antisemitism" fabricates a spurious continuity between the two figures mentioned and is thus an odious misrepresentation of Klein's position. Keywords: arithmetized analysis; axiomatisation of geometry; axiomatisation of physics; formalism; intuition; mathematical realism; modernism; Felix Klein; David Hilbert; Karl Weierstrass