Object recognition requires that you know when two shapes are 'similar'. But what does similar mean? The mathematician says: make the set of all (two dimensional, three dimensional or higher) shapes into the points of an infinite-dimensional space and then put a metric on this space reflecting what 'similar' means. The background image is supposed to suggest this construction: here a certain set of eggs with varying shapes are each put in its own pigeon-hole. If, for example, our 'shapes' are taken to be open subsets of Euclidean space with smooth boundaries, then this space will be a Banach or Frechet manifold, but a highly non-linear one. The question of finding the right mathematical model for the space of such shapes is not unlike moduli problems and I tried to get a grip on this as soon as I looked at vision problems.
Around 2004 I met Peter Michor and found that he had systematically developed the foundations of differential geometry of such infinite dimensional spaces. This seemed to be the right tool for studying the above spaces of shapes. Since then, we have been studying various Riemannian metrics on them and their associated completions; the geodesics in these metrics and the curvature of the space; examples and applications to object recognition.
MathWorld is the web's most extensive mathematical resource, provided as a free service to the world's mathematics and internet communities as part of a commitment to education and educational outreach by Wolfram Research, makers of Mathematica.
MathWorldTM is the web's most extensive mathematical resource, provided as a free service to the world's mathematics and internet communities as part of a commitment to education and educational outreach by Wolfram Research, makers of Mathematica.
Mathematics as a Non-Superstition. Eleven math courses (in the playlists), from high school (precalculus) to early graduate school (functional analysis), taught in such a way that the student should be able to defend (almost) all statements against objection.
Playlist List (sorted by last added):
Course 4: Linear Algebra
Course 3: Calculus II (US)
Course 2: Calculus I (Another extra)
Course 7: Principles of Mathematical Analysis
Course 9: Basic Functional and Harmonic Analysis
Course 8: Fourier Analysis
Course 8: Complex Analysis
Course 6: Introduction to Analysis
Course 5: Differential Equations
Course 4: Multivariable Calculus
Course 3: Calculus II
Course 2: Calculus I
Course 1: Precalculus
L. Wittgenstein. University Of Chicago Press, Chicago, (October 1989)characterizes mathematical propositions: - Do not have a temporal sense (pp. 34). - Are rules of expression. "the connection between a mathematical proposition and its application is roughly that between a rule of expression and the expression itself in use" (pp. 47). A rule of expression defines what is meaningful and what not, how a particular form should be used, etc. - Is invented to suit experience and then made independent of experience (pp. 43). "In mathematics we have propositions which contain the same symbols as, for example, "write down the integral of..", etc., with the difference that when we have a mathemaitical proposition time doesn't enter into it and in the other it does. Now this is not a metaphisical statement." (pp 34).
H. Freudenthal. Educational Studies in Mathematics, 1 (1/2):
3-8(May 1968)Systematization is a great virtue of mathematics, and if possible, the student has to learn this virtue, too. But then I mean the activity of systematizing, not its result. Its result is a system, a beautiful closed system, closed, with no entrance and no exit. In its highest perfection it can even be handled by a machine. But for what can be performed by machines, we need no humans. What humans have to learn is not mathematics as a closed system, but rather as an activity, the process of mathematizing reality and if possible even that of mathematizing mathematics..
P. Ernest. Why Learn Maths, London University Institute of Education, London, 1. To reproduce mathematical skill and knowledge based capability
The typical traditional reproductive mathematics curriculum has focused exclusively on this first aim, comprising a narrow reading of mathematical capability. At the highest level, not always realised, the learner learns to answer questions posed by the teacher or text. As is argued elsewhere (Ernest 1991) this serves not only to reproduce mathematical knowledge and skills in the learner, but to reproduce the social order and social injustice as well.
2. To develop creative capabilities in mathematics
The progressive mathematics teaching movement has added a second aim, to allow the learner to be creative and express herself in mathematics, via problem solving, investigational work, using a variety of representations, and so on. This allows the learner to pose mathematical questions, puzzles and problems, as well as to solve them. This notion adds the idea of creative personal development and the skills of mathematical questioning as a goal of schooling, but remains trapped in an individualistic ideology that fails to acknowledge the social and societal contexts of schooling, and thus tacitly endorses the social status quo.
3. To develop empowering mathematical capabilities and a critical appreciation of the social applications and uses of mathematics
Critical mathematics education adds in a third aim, the empowerment of the learner through the development of critical mathematical literacy capabilities and the critical appreciation of the mathematics embedded in social and political contexts. Thus the empowered learner will not only be able to pose and solve mathematical questions, but also be able to address important questions relating to the broad range of social uses (and abuses) of mathematics. This is a radical perspective and set of aims concerned with both the political and social empowerment of the learner and with the promotion of social justice, and which is realised in mainstream school education almost nowhere. However, the focus in the appreciation element developed in this perspective is on the external social contexts of mathematics. Admittedly these may include the history of mathematics and its past and present cultural contexts, but these do not represent any full treatment of mathematical appreciation.
4. To develop an inner appreciation of mathematics: its big ideas and nature
This fourth aim adds in further dimension of mathematical appreciation, namely the inner appreciation of mathematics, including the big ideas and nature of mathematics. The appreciation of mathematics as making a unique contribution to human culture with special concepts and a powerful aesthetic of its own, is an aim for school mathematics often neglected by mathematicians and users of mathematics alike. It is common for persons like these to emphasise capability at the expense of appreciation, and external applications at the expense of its inner nature and values. One mistake that may be made in this connection is the assumption that an inner appreciation of mathematics cannot be developed without capability. Thus, according to this assumption, the student cannot appreciate infinity, proof, catastrophe theory and chaos, for example, unless they have developed capability in these high level mathematical topics, which is out of the question at school. The fourth aim questions this assumption and suggests that an inner appreciation of mathematics is not only possible but desirable to some degree for all students at school..(2000)
L. Radford. Proceedings of the 29th Conference of the International Group for the Psychology of Mathematics Education, 1, page 143-145. Melbourne, Australia, University of Melbourne, (2005)