Standard part function: Difference between revisions

Revision as of 20:41, 21 May 2011

Revision as of 20:42, 21 May 2011

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[[Image:Gottfried Wilhelm von Leibniz.jpg|thumb|200px|right|''[[Gottfried Wilhelm Leibniz]]'' Inventor of [[infinitesimal calculus]] ]]

In [[non-standard analysis]], the '''standard part function''' "st" is a mathematical implementation of [[Pierre de Fermat]]'s [[adequality]]. It is the key ingredient in [[Abraham Robinson]]'s formalisation of Leibniz's informal[[infinitesimal]] definition (see [[ghosts of departed quantities]]) of the derivative as the ratio of two infinitesimals

:<math>\frac{dy}{dx}</math>,

see more at [[non-standard calculus]].