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In mathematics, a Diophantine equation is a polynomial equation, usually in two or more unknowns, such that only the integer solutions are sought or studied (an integer solution is a solution such that all the unknowns take integer values). A linear Diophantine equation is an equation between two sums of monomials of degree zero or one. An exponential Diophantine equation is one in which exponents on terms can be unknowns. Diophantine problems have fewer equations than unknown variables and involve finding integers that work correctly for all equations. In more technical language, they define an algebraic curve, algebraic surface, or more general object, and ask about the lattice points on it. The word ''Diophantine'' refers to the Hellenistic mathematician of the 3rd century, Diophantus of Alexandria, who made a study of such equations and was one of the first mathematicians to introduce symbolism into algebra. The mathematical study of Diophantine problems that Diophantus initiated is now called Diophantine analysis. While individual equations present a kind of puzzle and have been considered throughout history, the formulation of general theories of Diophantine equations (beyond the theory of quadratic forms) was an achievement of the twentieth century. ==Examples== In the following Diophantine equations, ''w'', ''x'', ''y'', and ''z'' are the unknowns and the other letters are given constants: = \frac + \frac + \frac||The Erdős–Straus conjecture states that, for every positive integer ''n'' ≥ 2, there exists a solution in ''x'', ''y'', and ''z'', all as positive integers. Although not usually stated in polynomial form, this example is equivalent to the polynomial equation 4''xyz'' = ''yzn'' + ''xzn'' + ''xyn'' = ''n''(''yz'' + ''xz'' + ''xy''). |- | ||Conjectured incorrectly by Euler to have no nontrivial solutions. Proved by Elkies to have infinitely many nontrivial solutions, with a computer search by Frye determining the smallest nontrivial solution. |} 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Diophantine equation」の詳細全文を読む スポンサード リンク
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