TITLE:
The Algebra of Projective Spheres on Plane, Sphere and Hemisphere
AUTHORS:
István Lénárt
KEYWORDS:
Projective Spheres, Binary Operation, Incidence Relation, Pappos, Desargues, Hesse-Chasles Configurations, Napier Pentagram and Hyperbolic Napier Pentagon, Polarity in Cartesian Coordinates, Differentiable Functions
JOURNAL NAME:
Journal of Applied Mathematics and Physics,
Vol.8 No.10,
October
30,
2020
ABSTRACT: Numerous authors studied polarities in incidence structures or algebrization of projective geometry [1] [2]. The purpose of the present work is to establish an algebraic system based on elementary concepts of spherical geometry, extended to hyperbolic and plane geometry. The guiding principle is: “The point and the straight line are one and the same”. Points and straight lines are not treated as dual elements in two separate sets, but identical elements within a single set endowed with a binary operation and appropriate axioms. It consists of three sections. In Section 1 I build an algebraic system based on spherical constructions with two axioms: ab = ba and (ab)(ac) = a, providing finite and infinite models and proving classical theorems that are adapted to the new system. In Section Two I arrange hyperbolic points and straight lines into a model of a projective sphere, show the connection between the spherical Napier pentagram and the hyperbolic Napier pentagon, and describe new synthetic and trigonometric findings between spherical and hyperbolic geometry. In Section Three I create another model of a projective sphere in the Cartesian coordinate system of the plane, and give methods and techniques for using the model in the theory of functions.