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Example of a polynomial equation, studied in elementary algebra
Example of a polynomial equation, studied in elementary algebra

Algebra is the branch of mathematics that studies certain abstract systems, known as algebraic structures, and the manipulation of statements within these systems. Elementary algebra generalizes arithmetic by using variables in addition to numbers. It covers methods of transforming equations to solve them by isolating variables. Linear algebra examines systems of several linear equations and techniques to determine for which values all equations in a system are true at the same time. Abstract algebra investigates algebraic structures, which consist of a set of objects together with operations defined on that set. It distinguishes algebraic structures, such as groups, rings, and fields, based on their number of operations and the laws they follow. Algebraic methods were first studied in ancient times to solve specific problems. As algebra evolved, it became increasingly abstract and generalized, leading to many applications in other branches of mathematics and the empirical sciences. (Full article...)

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Marcelo Rebelo de Sousa

Marcelo Rebelo de Sousa (born 12 December 1948) is a Portuguese politician and academic. He has been the 20th and current president of Portugal since 9 March 2016. As a member of the Social Democratic Party, he previously served as a minister and parliamentarian in the Assembly of the Republic. This photograph of Rebelo de Sousa was taken in 2017 at Web Summit, an annual technology conference held in Lisbon.

Photograph credit: João Pedro Correia

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