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Topic: Nonstandard analysis


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In the News (Tue 8 Dec 09)

  
  What is nonstandard analysis?
Nonstandard analysis (NSA) is a technique of mathematics which provides a logical foundation for the idea of an infinitesimal; a number which is less than 1/2, 1/3, 1/4, 1/5...
Abraham Robinson developed nonstandard analysis in the 1960's, and the theory has since been investigated for its own sake, and has been applied in areas such as Banach spaces, differential equations, probability theory, microeconomic theory and mathematical physics.
Nonstandard analysis is also sometimes referred to as infinitesimal analysis, or Robinsonian analysis.
members.tripod.com /PhilipApps/nonstandard.html   (409 words)

  
 Math Forum: Ask Dr. Math: A Mathematical Essay
Nonstandard Analysis and the Hyperreals, by Jordi Gutierrez Hermoso
Nonstandard analysis is a very rich and intricate topic, and I want to give as much of the complete story as possible, but I do not want to bog you down in technicalities.
With nonstandard analysis, the Leibniz notation for derivatives recovers the meaning its creator intended it to have (in standard analysis the Leibniz notation is used very sparingly because it is considered to be misleading).
mathforum.org /dr.math/faq/analysis_hyperreals.html   (9036 words)

  
  PlanetMath: non-standard analysis
Non-standard analysis is a branch of mathematics that formulates analysis using a rigorous notion of infinitesimal, where an element of an ordered field F is infinitesimal if and only if its absolute value is smaller than any element of F of the form 1/n, for n a natural number.
A field which satisfies the transfer principle for real numbers is a hyperreal field, and non-standard real analysis uses these fields as non-standard models of the real numbers.
This is version 2 of non-standard analysis, born on 2006-12-19, modified 2006-12-19.
planetmath.org /encyclopedia/NonStandardAnalysis.html   (559 words)

  
 [No title]
They cite earlier work from the late 60's, showing that N'th order nonstandard and standard "analysis" (in their sense) have exactly the same proof strength (in their sense), and that this is unchanged if one also adds axioms expressing the transfer principle and the *-operation.
For more conventionally expressive systems of analysis, such as ZFC, they cite results from the 1970's that nonstandard analysis together with saturation axioms is, once again, of exactly the same strength as standard analysis.
if a nonstandard real is a sequence of reals modulo sequences supported on sets of "measure" zero, the only relevant properties of measure 0 sets are that they include the finite sets, which leads back to the classical idiom of sequences tending to zero as being infinitesimal.
www.math.niu.edu /~rusin/known-math/00_incoming/nsa   (2761 words)

  
 Another View of Nonstandard Analysis
Nonstandard analysis provides powerful new tools not only for proving or refuting conjectures and simplifying standard proofs, but also for giving precise meaning to many informal notions - like large integers and neighboring points - useful for constructing mathematical models for diverse phenomena and in teaching calculus, analysis, and topology.
While nonstandard integers are too large to be uniquely specified, each has a decimal representatiion with a nonstandard number of digits, and students can compute with these in much the way that they do with standard integers, without reference to any formal theory; e.g.
To combine certain desirable features of both classifications, we introduce the notion that nonstandard integers are guests of Z rather than nonstandard members, and that these integers, their reciprocals, and certain other nonstandard numbers are guests of the ordered field R of reals.
www.haverford.edu /math/wdavidon/NonStd.html   (1480 words)

  
 A K Peters, Ltd. - Nonstandard Methods and Applications in Mathematics (paperback)
A conference on Nonstandard Methods and Applications in Mathematics(NS2002) was held in Pisa, Italy from June 12-16, 2002.
Nonstandard analysis is one of the great achievements of modern applied mathematical logic.
In addition to the important philosophical achievement of providing a sound mathematical basis for using infinitesimals in analysis, the methodology is now well established as a tool for both research and teaching, and has become a fruitful field of investigation in its own right.
www.akpeters.com /product.asp?ProdCode=2922   (205 words)

  
 Research Reports on Transfinite Graphs and Networks
After incidences and adjacencies between nonstandard vertices and edges are defined, several formulas regarding numbers of vertices and edges, and nonstandard versions of Eulerian graphs, Hamiltonian graphs, and a coloring theorem are established for these nonstandard graphs.
In a prior work the galaxies of the nonstandard enlargements of conventionally infinite graphs and also of transfinite graphs of the first rank of transfiniteness were defined, examined, and illustrated by some examples.
  Nonstandard analysis shows that, when the wires are taken to have infinitesimally small but nonzero resistance, the energy dissipated in the wires equals the substantial amount of energy that had disappeared, and that all but an infinitesimal amount of this dissipation occurs during an infinitesimal initial time period.
www.ece.sunysb.edu /~zeman/researchtgn.html   (2624 words)

  
 Non-standard analysis - Wikipedia, the free encyclopedia
One pedagogical application of non-standard analysis is Edward Nelson's treatment of the theory of stochastic processes, presented in his monograph Radically Elementary Probability Theory.
There are two very different approaches to non-standard analysis: the semantic or model-theoretic approach and the syntactic approach.
Despite its elegance and simplicity, syntactic non-standard analysis requires a great deal of care in applying the principle of set formation (formally known as the axiom of comprehension) which mathematicians usually take for granted.
en.wikipedia.org /wiki/Non-standard_analysis   (2356 words)

  
 Philosophical Problems with Calculus
However, nonstandard analysis is not yet as simple as the old Leibniz calculus of infinitesimals, and there is a continuing search for a really natural system that uses infinitesimals in a consistent way.
But, as John Stillwell says in the epigraph, "...nonstandard analysis is not yet as simple as the old Leibniz calculus of infinitesimals, and there is a continuing search for a really natural system that uses infinitesimals in a consistent way." So even some mathematicians are left with a desire for something better.
The extra axioms of nonstandard analysis may provide a breathing space for them, but, as Stillwell says, it would be nice to have "a really natural system" that can define infinitesimals in way that would not offend the intelligence of Thomas Hobbes or anyone else.
www.friesian.com /calculus.htm   (3748 words)

  
 Nonstandard Analysis   (Site not responding. Last check: 2007-10-30)
Nonstandard Analysis in Operator Theory and Mathematical Physics
In treating very complex problems of quantum theory and mathematical physics often one encounters difficult limiting procedures which may be solved especially easy (and in most cases for the first time) by methods of nonstandard analysis.
In all of these problems the possibility to treat "infinitely small" and "infinitely large" quantities in a mathematically rigorous way using nonstandard analysis leads to new insights and solutions.
www.uni-tuebingen.de /uni/mmm/nonstandard.html   (128 words)

  
 classical > nonstandard
Nonstandard analysis is a branch of mathematical logic which introduces hyperreal numbers to allow...
Nonstandard analysis is a branch of mathematical logic which introduces hyperreal numbers to...
Nonstandard analysis (NSA) is a technique of mathematics which provides a logical foundation for the idea of an infinitesimal; a number which is less than 1/2, 1/3, 1...
www.cantoantiguo.com /classical/nonstandard.php   (229 words)

  
 pref
The earliest practice of nonstandard analysis, concentrated on a variety of different nonstandard extensions of ``standard'' mathematical structures, was codified by Robinson and Zakon in the late 60s.
a system, of type-theoretic character, which reduced methods of nonstandard analysis to a few principles, which, once established, allow to develop nonstandard analysis without paying much attention to details related to the construction of nonstandard extensions.
to demonstrate how ``nonstandard'' arguments (in domains which vary from traditional topics like calculus to those which attract attention nowadays like ``hyperfinite'' descriptive set theory) can be maintained on the base of HST -- where we build upon research papers and, occasionally, books (with respect to more traditional material) in nonstandard analysis.
www.math.uni-wuppertal.de /~reeken/pref.html   (2554 words)

  
 Nonstandard Analysis 1996/97
In 1960 A Robinson gave a rigorous foundation for the use of infinitesimals in analysis.
It is a powerful new tool for mathematical research, which has led to many new insights into traditional mathematics, and to solutions of unsolved problems in areas as diverse as functional analysis, probability theory, complex function theory, potential theory, mathematical physics, and mathematical economics.
Applications to a topological context: nonstandard hulls, compactness, and metric spaces, normed spaces, Hilbert spaces.
www.math.chalmers.se /Math/Foutb/Kurser9697/nonstandard-en.html   (164 words)

  
 Nonstandard topology, by Paul Bankston   (Site not responding. Last check: 2007-10-30)
Nonstandard topology bears the same conceptual relationship to nonstandard analysis as ordinary topology does to classical analysis; namely the former provides a very fruitful generalization of the latter for the purposes of treating such basic concepts as the continuity of functions.
This approach was devised by the logician Abraham Robinson in 1960 partly to vindicate the Leibnizian notions of "infinitesimal" and "monad," which, up to that time, had only intuitive appeal and no mathematical foundation, but mostly to create a powerful new research method for mathematics in general.
If the original structure is a topological space, there are not only nonstandard points in the enlargement but nonstandard open sets as well.
at.yorku.ca /z/a/a/b/06.htm   (320 words)

  
 Springer Online Reference Works
A branch of mathematical logic concerned with the application of the theory of non-standard models to investigations in traditional domains of mathematics: mathematical analysis, function theory, the theory of differential equations, probability theory, and others.
Leibniz and his followers, about the existence of infinitely small non-zero quantities, on a strict mathematical basis, a circle of ideas which in the subsequent development of mathematical analysis was rejected in favour of the precise concept of the limit of a variable quantity.
Non-standard analysis has been used successfully in constructing a rigorous theory of certain semi-empirical methods of mechanics and physics.
eom.springer.de /n/n067320.htm   (518 words)

  
 A Nonstandard Proof of the Fundamental Theorem of Algebra American Mathematical Monthly, The - Find Articles   (Site not responding. Last check: 2007-10-30)
Real analysis, for example, is a theory that has an intended model: the collection of all real numbers, defined as sets of rational numbers, Dedekind cuts.
Leibniz introduced this notation based on his hypothesis that infinitesimals were actual quantities, and the notation survived even as infinitesimals (except when used by Euler) were banned from mathematical discourse as "ghosts of departed quantities"1 until they were resurrected in the mid-twentieth century.
The theorems of real analysis are valid for the hyperreals because the latter satisfy all the axioms used in proving these theorems.
www.findarticles.com /p/articles/mi_qa3742/is_200510/ai_n15715107   (947 words)

  
 Applied Nonstandard Analysis
Geared toward upper-level undergraduates and graduate students, this text assumes no knowledge of mathematical logic; it develops the key techniques of nonstandard analysis at the outset from a single, powerful construction.
Then, beginning with a nonstandard construction of the real number system, it leads students thorough the basic topics of elementary real analysis, topological spaces, and Hilbert space.
This short, readable introduction to nonstandard analysis is based on the axiomatic IST (internal set theory) approach.
store.doverpublications.com /0486442292.html   (211 words)

  
 Connes on nonstandard analysis; Dixmier trace   (Site not responding. Last check: 2007-10-30)
From every nonstandard real number one can >construct canonically a subset of the interval [0, 1], which is NOT Lebesque >measurable.
But anyway, the above paragraph does not "destroy" nonstandard analysis, unless you believe that the axiom of choice is wrong, in which case a large part of mathematics also go up in flames.
The pros and cons of the axiom of choice have been debated extensively for almost a century, and this is certainly the not the place to attempt to settle that dispute.
www.lns.cornell.edu /spr/1999-12/msg0019983.html   (914 words)

  
 [No title]
Laugwitz, D. : Omega-calculus as a generalisation of field extension - an alternative approach to nonstandard analysis, in: A.E. Hurd (ed.) Non-standard Analysis - Recent Developments, Lecture Notes in Mathematics, Vol.
Liu, S.-C.: A proof-theoretic approach to nonstandard analysis with emphasis on distinguishing between constructive and non-constructive results, in: H.J. Keisler and K. Kunen (eds.), The Kleene Symposium, North-Holland, Amsterdam 1980, 391 - 414.
Palmgren, E.: A sheaf-theoretic foundation for nonstandard analysis, Uppsala University, Department of Mathematics Report 1995:43 (to appear in Ann.
www.math.uu.se /~palmgren/biblio/nonstd.html   (247 words)

  
 LMS JCM (3) 140-190   (Site not responding. Last check: 2007-10-30)
The theory, which includes infinitesimals and infinite numbers, is based on the hyperreal number system developed by Abraham Robinson in his nonstandard analysis (NSA).
The current work provides both standard and nonstandard definitions for the various notions, and proves their equivalence in each case.
The merits of the nonstandard approach with respect to the practice of analysis and mechanical theorem-proving are highlighted throughout the exposition.
www.lms.ac.uk /jcm/3/lms1999-027   (273 words)

  
 CiteULike: Lectures on the Hyperreals : An Introduction to Nonstandard Analysis (Graduate Texts in Mathematics)   (Site not responding. Last check: 2007-10-30)
This is an introduction to nonstandard analysis based on a course of lectures given several times by the author.
It presents nonstandard analysis not just as a theory about infinitely small and large numbers, but as a radically different way of viewing many standard mathematical concepts and constructions; a source of new ideas, objects and proofs; and a wellspring of powerful new principles of reasoning (transfer, overflow, saturation, enlargement, hyperfinite approximation etc.).
The book begins with the ultrapower construction of hyperreal number systems, and proceeds to develop one-variable calculus, analysis and topology from the nonstandard perspective, emphasizing the role of the transfer principle as a working tool of mathematical practice.
www.citeulike.org /user/david_lewis/article/566503   (520 words)

  
 Ultrafilters, nonstandard analysis, and epsilon management « What’s new
There is however, a way to make concepts such as “the set of all bounded numbers” precise and meaningful, by using non-standard analysis, which is the most well-known of the “pseudo-finitary” approaches to analysis, in which one adjoins additional numbers to the standard number system.
I hope I have shown that non-standard analysis is not a totally “alien” piece of mathematics, and that it is basically only “one ultrafilter away” from standard analysis.
You observe that “For the purposes of non-standard analysis, one non-principal ultrafilter is much the same as any other.” A few years ago, after he gave a talk on surreal numbers, I had a brief discussion with John Conway about nonstandard analysis.
terrytao.wordpress.com /2007/06/25/ultrafilters-nonstandard-analysis-and-epsilon-management   (8092 words)

  
 Introduction to Non-Standard Analysis by Fred Kidd — science, mathematics, infinitesimals | Gather   (Site not responding. Last check: 2007-10-30)
He was finally awarded a graduate degree from the Hebrew University in 1946 and became a pioneer in model theory.
Non-Standard Analysis, or NSA, sometimes referred to as infinitesimal analysis, is the "alternate lifestyle" of mathematics.
The real numbers are sometimes referred to as "standard" numbers, which gave rise to naming this new form of math "Non-Standard Analysis", because the hyperreals that are not real numbers are referred to as "nonstandard".
www.gather.com /viewArticle.jsp?articleId=281474976755323   (1248 words)

  
 Nonstandard Analysis
Also, the completeness of real arithmetic works against analysis; the algebraic numbers are also a model of the theory of real arithmetic, and transcendental functions cannot exist among the algebraic numbers...
So, clearly, this simle theory is not sufficient to do nonstandard analysis.
What you probably want is in chapters 1 and 2, including superstructures, formal languages, Los and transfer theorems and the application to real numbers.
www.physicsforums.com /showthread.php?t=8056   (1600 words)

  
 Math 489-Infinitesimal Analysis
Two fundamentally different modern approaches to infinitesimals have been developed which recapture the intuition which was so successful for Leibniz and the Bernoulli family: synthetic differential geometry and nonstandard analysis.
The main focus of the course, occupying the first two thirds of the course, will be the development of calculus in a smooth world using infinitesimals which have powers giving 0, the approach of synthetic differential geometry.
In non-standard analysis we are careful about the logical structure of the statements we make and use an extension of the usual reals to include invertible infinitesimals.
www.iwu.edu /~lstout/InfinitesimalAnalysis/syl489s01.html   (740 words)

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