ALGEBRA
[From the Encyclopedia Brittanica]
Algebra is a branch of mathematics in which arithmetical operations and formal manipulations are applied to abstract symbols rather than specific numbers. The notion that there exists such a distinct subdiscipline of mathematics, as well as the term algebra to denote it, resulted from a slow historical development.
The academic discipline of Algebra developed over time through the concept of the equation, number systems, symbols for conveying and manipulating mathematical statements, and the modern abstract structural view of algebra. For information on specific branches of algebra, see elementary algebra, linear algebra, and modern algebra.
Emergence of formal equations
Perhaps the most basic notion in mathematics is the equation, a formal statement that two sides of a mathematical expression are equal—as in the simple equation x + 3 = 5—and that both sides of the equation can be simultaneously manipulated (by adding, dividing, taking roots, and so on to both sides) in order to “solve” the equation. Yet, as simple and natural as such a notion may appear today, its acceptance first required the development of numerous mathematical ideas, each of which took time to mature. In fact, it took until the late 16th century to consolidate the modern concept of an equation as a single mathematical entity.
Three main threads in the process leading to this consolidation deserve special attention:
Attempts to solve equations involving one or more unknown quantities. In describing the early history of algebra, the word equation is frequently used out of convenience to describe these operations, although early mathematicians would not have been aware of such a concept.
The evolution of the notion of exactly what qualifies as a legitimate number. Over time this notion expanded to include broader domains (rational numbers, irrational numbers, negative numbers, and complex numbers) that were flexible enough to support the abstract structure of symbolic algebra.
The gradual refinement of a symbolic language suitable for devising and conveying generalized algorithms, or step-by-step procedures for solving entire categories of mathematical problems.