Advances in Analysis, Probability and Mathematical Physics

In 1961 Robinson introduced an entirely new version of the theory of infinitesimals, which he called `Nonstandard analysis''. `Nonstandard'' here refers to the nature of new fields of numbers as defined by nonstandard models of the first-order theory of the reals. This system of numbers was closely related to the ring of Schmieden and Laugwitz, developed independently a few years earlier.
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