arXiv subjects
Publications and source records attributed to Abraham A. Ungar.
A gyrogroup is a structure constituting from a non-empty set and a binary operation such that satisfying the left identity, and left inverse conditions, and also has the associative-like law said to be left gyroassociativity and left loop property. In this paper, we propose a method for constructing new gyrogroups of order $2^n$ by a cyclic 2-group that is $\mathbb{Z}_{2^n}$, where $n\geq 3$.
The decomposition $Γ=BH$ of a group $Γ$ into a subset $B$ and a subgroup $H$ of $Γ$ induces, under general conditions, a group-like structure for $B$, known as a gyrogroup. The famous concrete realization of a gyrogroup, which motivated the emergence of gyrogroups into the mainstream, is the space of all relativistically admissible velocities along with a binary operation given by the Einstein velocity addition law of special relativity theory. The latter leads to the Lorentz transformation group $\mathrm{SO}(1,n)$, $n\in\mathbb{N}$, in pseudo-Euclidean spaces of signature $(1, n)$. The study in this article is motivated by generalized Lorentz groups $\mathrm{SO}(m, n)$, $m, n\in\mathbb{N}$, in pseudo-Euclidean spaces of signature $(m, n)$. Accordingly, this article explores the bi-decomposition $Γ= H_LBH_R$ of a group $Γ$ into a subset $B$ and subgroups $H_L$ and $H_R$ of $Γ$, along with the novel bi-gyrogroup structure of $B$ induced by the bi-decomposition of $Γ$. As an example, we show by methods of Clifford algebras that the quotient group of the spin group $\mathrm{spin}(m, n)$ possesses the bi-decomposition structure.
The Lorentz transformation group $SO(m,n)$ is a group of Lorentz transformations of order $(m,n)$, that is, a group of special linear transformations in a pseudo-Euclidean space of signature $(m,n)$ that leave the pseudo-Euclidean inner product invariant. A parametrization of $SO(m,n)$ is presented, giving rise to the composition law of Lorentz transformations of order $(m,n)$ in terms of parameter composition. The parameter composition, in turn, gives rise to a novel group-like structure called a bi-gyrogroup. Bi-gyrogroups form a natural generalization of gyrogroups where the latter form a natural generalization of groups. Like the abstract gyrogroup, the abstract bi-gyrogroup can play a universal computational role which extends far beyond the domain of pseudo-Euclidean spaces.
Barycentric coordinates are commonly used in Euclidean geometry. Following the adaptation of barycentric coordinates for use in hyperbolic geometry in recently published books on analytic hyperbolic geometry, known and novel results concerning triangles and circles in the hyperbolic geometry of Lobachevsky and Bolyai are discovered. Among the novel results are the hyperbolic counterparts of important theorems in Euclidean geometry. These are: (1) the Inscribed Gyroangle Theorem, (ii) the Gyrotangent-Gyrosecant Theorem, (iii) the Intersecting Gyrosecants Theorem, and (iv) the Intersecting Gyrochord Theorem. Here in gyrolanguage, the language of analytic hyperbolic geometry, we prefix a gyro to any term that describes a concept in Euclidean geometry and in associative algebra to mean the analogous concept in hyperbolic geometry and nonassociative algebra. Outstanding examples are {\it gyrogroups} and {\it gyrovector spaces}, and Einstein addition being both {\it gyrocommutative} and {\it gyroassociative}. The prefix "gyro" stems from "gyration", which is the mathematical abstraction of the special relativistic effect known as "Thomas precession".
In this chapter, dedicated to the 60th Anniversary of Themistocles M. Rassias, Möbius transformation and Einstein velocity addition meet in the hyperbolic geometry of Bolyai and Lobachevsky. It turns out that Möbius addition that is extracted from Möbius transformation of the complex disc and Einstein addition from his special theory of relativity are isomorphic in the sense of gyrovector spaces.
In this era of an increased interest in loop theory, the Einstein velocity addition law has fresh resonance. One of the most fascinating aspects of recent work in Einstein's special theory of relativity is the emergence of special grouplike loops. The special grouplike loops, known as gyrocommutative gyrogroups, have thrust the Einstein velocity addition law, which previously has operated mostly in the shadows, into the spotlight.
The analytic hyperbolic geometric viewpoint of Einstein's special theory of relativity is presented.
Being neither commutative nor associative, Einstein velocity addition of relativistically admissible velocities gives rise to gyrations. Gyrations, in turn, measure the extent to which Einstein addition deviates from commutativity and from associativity. Gyrations are geometric automorphisms abstracted from the relativistic mechanical effect known as Thomas precession.
The evolution from Mobius to gyrogroups began in 1988, and is still ongoing in [14, 15]. Gyrogroups, a natural generalization of groups, lay a fruitful bridge between nonassociative algebra and hyperbolic geometry, just as groups lay a fruitful bridge between associative algebra and Euclidean geometry. More than 150 years have passed since the German mathematician August Ferdinand Mobius first studied the transformations that now bear his name. Yet, the rich structure he thereby exposed is still far from being exhausted, as the evolution from Mobius to gyrogroups demonstrates.
In this paper, we present a measure to quantify the degree of entanglement for two qubits in a pure state.
In this Brief Report, we present a geometric observation for the Bures fidelity between two states of a qubit.