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Topic: Frechet space


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In the News (Thu 31 Dec 09)

  
 Fréchet space
Spaces of inifinitely often differentiable functions defined on compact sets are typical examples.
The space of all sequences of real numbers becomes a Fréchet space if we define the k-th semi-norm of a sequence to be the absolute value of the k-th element of the sequence.
This is in stark contrast to the situation in Banach spaces.
www.ebroadcast.com.au /lookup/encyclopedia/fr/Frechet_space.html   (792 words)

  
 F-space
In functional analysis, an F-space is a vector space V over the real or complex numbers together with a metric d : V × V → R so that
Clearly, all Banach spaces and Fréchet spaces are F-spaces.
spaces for 0 < p < 1 are examples of F-spaces which are not Fréchet spaces.
www.ebroadcast.com.au /lookup/encyclopedia/f-/F-space.html   (114 words)

  
 PlanetMath: Fréchet space
An F-space is a complete topological vector space whose topology is induced by a translation invariant metric.
Recall that a topological vector space is a uniform space.
A Fréchet space is a complete topological vector space (either real or complex) whose topology is induced by a countable family of semi-norms.
planetmath.org /encyclopedia/FSpace.html   (482 words)

  
 A Space -- Recommendations and Resources   (Site not responding. Last check: 2007-10-14)
One view of space is that it is part of the fundamental structure of the universe, a set of dimensions in which objects are separated and located, have size and shape, and through which they can move.
A contrasting view is that space is part of a fundamental abstract mathematical conceptual framework (together with time and number) within which we compare and quantify the distance between objects, their sizes, their shapes, and their speeds.
Space is typically described as having three dimensions, and that three numbers are needed to specify the size of any object and/or its location with respect to another location.
www.becomingapediatrician.com /health/0/a-space.html   (1235 words)

  
 convergence spaces   (Site not responding. Last check: 2007-10-14)
Convergence spaces are for topological spaces like complex numbers are for real numbers; where some topological problems fail to find their solutions in topologies, they will, however, in convergences.
The class of sequential topological spaces is of particular interest, on one hand because it is exactly the class of spaces for which sequences suffice to describe the topology, on the other hand because this is exactly the class of topological quotient of metrizable spaces.
The subclass of sequential spaces that are stable under subspaces is that of Fréchet-Urysohn spaces.
www.cs.georgiasouthern.edu /faculty/mynard_f/convergences.htm   (3488 words)

  
 CS507 Project - Computing the Fréchet distance between two polygonal curves
Also, the free space corresponding to two line segments is the intersection of the unit square with an ellipse, possibly degenerated to the space between two parallel lines.
The free space corresponding to the curves P and Q is the combination of the free spaces of all pairs containing one segment of P and one segment of Q.
As the free space of each unit cell is convex, it is an easy matter to determine if there is a monotone curve that goes from (0,0) to (p, q) by computing all the intersections of the free space with the contour of each cell.
www.cim.mcgill.ca /~stephane/cs507/Project.html   (1857 words)

  
 Fréchet space - Wikipedia, the free encyclopedia
Fréchet spaces, in contrast, are locally convex spaces which are complete with respect to a translation invariant metric.
Fréchet spaces are studied because even though their topological structure is more complicated due to the lack of a norm, many important results in functional analysis, like the open mapping theorem and the Banach-Steinhaus theorem, still hold.
Spaces of infinitely often differentiable functions defined on compact sets are typical examples of Fréchet spaces.
en.wikipedia.org /wiki/Fr%C3%A9chet_space   (937 words)

  
 [No title]
By this means the space of distributions and the space of hyperfunctions on the circle become locally convex topological vector spaces.
A Frechet space is a locally convex F-space.
A topological vector space is a Frechet space in Rudin's sense if and only if it is complete and its topology is determined by a countable family of (continuous) seminorms.
www.math.niu.edu /~rusin/known-math/98/TVS   (906 words)

  
 Fréchet Space -- from Wolfram MathWorld
A Fréchet space is a complete and metrizable space, sometimes also with the restriction that the space be locally convex.
The topology of a Fréchet space is defined by a
Its topology is the C-infty topology, which is given by the countable family of
mathworld.wolfram.com /FrechetSpace.html   (128 words)

  
 Springer Online Reference Works
A term used to designate a measure given in a topological vector space when one wishes to stress those properties of the measure that are connected with the linear and topological structure of this space.
A general problem encountered in the construction of a measure in a topological vector space is that of extending a pre-measure to a measure.
Integral over trajectories), and also with the theory of generalized random fields, and is to a high degree stimulated by the applications of these theories in physics and mechanics.
eom.springer.de /m/m063250.htm   (567 words)

  
 Topological vector space - Wikipedia, the free encyclopedia (via CobWeb/3.1 planetlab2.cs.virginia.edu)   (Site not responding. Last check: 2007-10-14)
As the name suggests the space blends a topological structure (a uniform structure to be precise) with the algebraic concept of a vector space.
A topological vector space X is a vector space over a topological field K (most often the real or complex numbers with their standard topologies) which is endowed with a topology such that vector addition X × X → X and scalar multiplication K × X → X are continuous functions.
A vector space is an abelian group with respect to the operation of addition, and in a topological vector space the inverse operation is always continuous (since it is the same as multiplication by −1).
en.wikipedia.org.cob-web.org:8888 /wiki/Topological_vector_space   (1116 words)

  
 Springer Online Reference Works
A barrelled space (in particular, a Fréchet space) in which each closed bounded set is compact.
The strong dual of a Montel space is a Montel space; in particular, the spaces of generalized functions
A normed space is a Montel space if and only if it is finite-dimensional.
eom.springer.de /m/m064880.htm   (187 words)

  
 Prof. Dr. Ralf Meyer
For the underlying metric space of a group, the coarse co-assembly map is closely related to the existence of a dual Dirac morphism and thus to the Dirac dual Dirac method of attacking the Novikov conjecture.
Using natural spaces of functions on the adele ring and the idele class group of K, we construct a virtual representation of the idele class group of K whose character is equal to the Weil distribution that occurs in André Weil's Explicit Formula.
The consideration of square-integrable representations of Abelian groups on Hilbert space shows that this condition is not sufficient and that different choices for R may yield different generalized fixed point algebras.
www.uni-math.gwdg.de /rameyer   (2227 words)

  
 1
Mogilski, Hereditarily negligible subsets of infinite-dimensional Frechet manifolds, Bull.
Dobrowolski and J. Mogilski, Sigma-compact locally convex metric linear spaces universal for compacta are homeomorphic, Proc.
J.J. Dijkstra, J. Mogilski, A geometric approach to the  dimension theory of infinite-dimensional spaces, Proceedins of the Eight Annual Workshop in Geometric Topology in Milwaukee (1991), 59-63.
blue.utb.edu /jkm/publications.htm   (432 words)

  
 [No title]   (Site not responding. Last check: 2007-10-14)
If the convergence of a sequence to zero is meant to be "uniform convergence of all derivatives, and all supports of these functions can be included in the same compact set", then this vector space is not even metrizable, much less normable, and much less normable with a complete norm (to become a Banach space).
If you drop that restriction, the space becomes metrizable but not complete (if it were complete, it would be called Frechet space, rather than Banach space.
And a Frechet space can fail to be locally convex, and can have only a trivial dual, making many problems much harder (such as optimization).) My imagination does not go far enough to give me an idea what the completion would be.
www.math.niu.edu /~rusin/known-math/99/cpt_support   (307 words)

  
 Maurice-René Fréchet Biography | World of Scientific Discovery
A point is a common example of one-dimensional real space and a line, an example of two-dimensional real space.
He generalized the point set topology that had been developed for Euclidean space by introducing a topology based on a generalized concept of a distance function in an abstract space.
Such spaces later came to be called metric spaces.
www.bookrags.com /biography/maurice-rene-frechet-wsd   (401 words)

  
 AMCA: Dynamics of linear operators on non-metrizable vector spaces by Jose Bonet   (Site not responding. Last check: 2007-10-14)
The proof depends on the existence of a dense subspace which is a Fréchet space for a stronger topology, hence the conclusion follows from Baire theorem and a comparison principle.
This kind of reduction to the Fréchet case fails if one considers spaces of test functions such as D, which is a strict inductive limit of Fréchet spaces.
The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Mathematical Conference Abstracts.
at.yorku.ca /c/a/p/a/28.htm   (358 words)

  
 First-countable, Sequential, and Frechet Spaces
Next there are some facts about them, that every first-countable space is Frechet and every Frechet space is sequential.
Families of subsets, subspaces and mappings in topological spaces.
Metric spaces as topological spaces --- fundamental concepts.
www.mizar.org /JFM/Vol10/frechet.html   (147 words)

  
 OPERATOR THEORY, SYSTEM THEORY AND SCATTERING THEORY: MULTIDIMENSIONAL GENERALIZATIONS
We define and study some finite-dimensional resolvent-invariant subspaces that generalize the finite-dimensional de Branges-Rovnyak spaces to the setting of the ball.
The transfer function becomes a bundle map between the input and output bundles which is contractive with respect to certain parahermitian forms on these bundles.
The simplest positivity condition is, perhaps, that characterizing a Hilbert space contraction C, i.e.
www.cs.bgu.ac.il /~dany/abst3/abst3.html   (1611 words)

  
 Space A -- Recommendations and Resources   (Site not responding. Last check: 2007-10-14)
Known Space is the fictional setting of many of Larry Niven's science fiction stories.
I suggest an entry that defines space as geographers may see it.
It admits no continuous seminorms and no continuous linear functionals — it has trivial dual space.
www.becomingapediatrician.com /health/135/space-a.html   (1236 words)

  
 Diary for Math 507:01, spring 2004
The second has a Frechet space structure, and it has neighborhoods of 0 which are convex.
Although all Hilbert spaces are "the same"(depending on the cardinality of an orthonormal basis) [I mean all "places" in H are sort of the same] the operators are very very very different and complicated.
If K is finite, then the Hilbert space dimensional is the same as the number of elements of K, and is the same as the linear algebra dimension of K. If K is infinite, then the equation (countable)·(infinite)=same infinite shows that the cardinality of K doesn't change.
www.math.rutgers.edu /~greenfie/mill_courses/math507/diary.html   (4537 words)

  
 Maurice-René Fréchet Biography | World of Invention
His fourth dimension--time--suggests another level of reality beyond the immediate, apparent, and static three-dimensional world with which we are familiar.
That is, a person living on a plane surface (two-dimensional space) might be able to predict what three dimensions are like, based on what she or he knows about her or his own world.
Fréchet used a similar technique to describe space with more dimensions than the three or four with which we are familiar.
www.bookrags.com /biography/maurice-rene-frechet-woi   (406 words)

  
 Contents of volume 49, No   (Site not responding. Last check: 2007-10-14)
The least infinite-dimensionality for Fréchet spaces is c (Mazur), for metrizable barrelled spaces, b (Saxon and Sánchez Ruiz, 1996).
For metrizable spaces with the yet weaker inductive property, it is the dimension N
The inversion formulas obtained are similar to the inversion formulas in symmetric space of noncompact type (see [7], [18], [19]).
www.pan.pl /bulletin/MATH/Mat_2_01.html   (548 words)

  
 September 2 - Today in Science History   (Site not responding. Last check: 2007-10-14)
He is credited with being the founder of the theory of abstract spaces, which generalized the traditional mathematical definition of space as a locus for the comparison of figures; in Fréchet's terms, space is defined as a set of points and the set of relations.
In his dissertation of 1906, he investigated functionals on a metric space and formulated the abstract notion of compactness.
In 1993, the United States and Russia formally ended decades of competition in space by agreeing to a joint venture to build a space station.
www.todayinsci.com /9/9_02.htm   (1556 words)

  
 Contents of Issue 3/98   (Site not responding. Last check: 2007-10-14)
The spaces of Borel probabilities on a topological space X inherit a number of topological properties of X.
It is shown that the space O(X) is homeomorphic to the Tychonov cube I
It is shown that in the space of all nonexpansive continuous IFS´s defined on a compact convex subset of R
www.pan.pl /bulletin/MATH/m1-99.htm   (682 words)

  
 Eric Van Douwen's papers
Compactness-like properties and nonnormality of the space of nonstationary ultrafilters.
A compact space with a measure that knows which sets are homeomorphic.
A regular space on which every continuous real-valued function is constant.
www.math.buffalo.edu /~sww/0papers/van_douwen_eric_k.html   (2009 words)

  
 Citebase - Sequential convergence in topological spaces   (Site not responding. Last check: 2007-10-14)
In this way I have been led to consider five different classes of topological spaces: first countable spaces, sequential spaces, Frechet spaces, spaces of countable tightness and perfect spaces.
For instance, we examine an example of a Frechet space with unique sequential limits that is not Hausdorff.
The results that we prove below include characterisation theorems of sequential spaces and Frechet spaces in terms of appropriate classes of continuous mappings, and the theorem that every perfectly regular countably compact space has countable tightness.
www.citebase.org /cgi-bin/citations?id=oai:arXiv.org:math/0412558   (276 words)

  
 Indagationes Mathematicae.   (Site not responding. Last check: 2007-10-14)
Wieslaw liwa, Every infinite-dimensional non-archimedean Fréchet space has an orthogonal basic sequence, Indagationes Mathematicae 11 (3) (2000) pp.
J.E. Vaughan, Zero-dimensional spaces from linear structures, Indagationes Mathematicae 12 (4) (2001) pp.
Nowak, Weak compactness in Kothe-Bochner spaces and Orlicz-Bochner spaces, Indagationes Mathematicae 10 (1) (1999) pp.
www1.elsevier.com /cdweb/journals/00193577/viewer.htt?viewtype=keywords   (337 words)

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