On the algebraic structure of Pythagorean triples

A Pythagorean triple is an ordered triple of integers (a,b,c) ≠ (0, 0, 0) such that a^2 + b^2 = c^2. It is well known that the set ℘ of all Pythagorean triples has an intrinsic structure of commutative monoid with respect to a suitable binary operation (℘,⋆). In this article, we will introduce the &...

Full description

Bibliographic Details
Main Authors: Giuseppina Anatriello, Giovanni Vincenzi
Format: Article
Language:English
Published: Accademia Peloritana dei Pericolanti 2024-02-01
Series:Atti della Accademia Peloritana dei Pericolanti : Classe di Scienze Fisiche, Matematiche e Naturali
Online Access: http://dx.doi.org/10.1478/AAPP.1021A3
Description
Summary:A Pythagorean triple is an ordered triple of integers (a,b,c) ≠ (0, 0, 0) such that a^2 + b^2 = c^2. It is well known that the set ℘ of all Pythagorean triples has an intrinsic structure of commutative monoid with respect to a suitable binary operation (℘,⋆). In this article, we will introduce the "commensurability" relation ℛ among Pythagorean triples, and we will see that it induces a group quotient, ℘/ℛ, which is isomorphic with the direct product of infinite (countable) copies of C∞, the infinite cyclic group, and a cyclic group of order 4. As an application, we will see that the acute angles of Pythagorean triangles are irrational when measured in degrees.
ISSN:0365-0359
1825-1242