Sunday, March 28, 2021 at 1:28 PM
- written by user ΑΡΒΑΝΙΤΗΣ ΣΤΥΛΙΑΝΟΣ

We have examined further details on boundness including: several (counter-) examples of boundness in function spaces using uniform boundness, some limiting variance, a characterization of boundedness for metric subspaces, and an equivalent definition that is useful for the introduction of total boundness.

Notes on the above can be found here, here, and here. The lectures whiteboards can be found  here

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Sunday, March 21, 2021 at 11:12 PM
- written by user ΑΡΒΑΝΙΤΗΣ ΣΤΥΛΙΑΝΟΣ

We continued our study of ball properties and have shown that the local information that they convey about their center, can be conveyed by a "countable description", as well as that there exists an antimonotone relation between the open (closed) balls of fixed center and radius w.r.t. metrics that obey functional inequalities confirming the aforementioned remark concerning gif.latex?%5Cmathbb%7BR%7D%5E%7Bn%7D

We begun our study of metric properties with the finitary notion of boundness. The balls can be readily used in order to

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Sunday, March 14, 2021 at 11:06 PM
- written by user ΑΡΒΑΝΙΤΗΣ ΣΤΥΛΙΑΝΟΣ

We examined the important example of the space of bounded real functions on a non-empty domain endowed with the uniform metric and showed that it contains several subexamples, e.g. the spaces of real n-vectors equipped with the max-metric.

We completed our general definitions with the notion of the metric subspace. This as well as  the notion of product metric spaces (with a finite number of factors) can be viewed as ways to construct further metric spaces from given one(s), with the resulting m

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Sunday, March 7, 2021 at 5:22 PM
- written by user ΑΡΒΑΝΙΤΗΣ ΣΤΥΛΙΑΝΟΣ

We went through with the examination of several examples of such spaces, including the Hamming distance, as well as distances defined on sets of real finite dimensional vectors.

(Some of) The examples have shown that it is possible that different metrics on the same carrier set can obey relations, e.g. in the form of functional inequalities. We suspected that such relations might imply analogous ones between the relevant properties that each metric endows the space with, and that provides as wit

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Sunday, February 28, 2021 at 2:25 AM
- written by user ΑΡΒΑΝΙΤΗΣ ΣΤΥΛΙΑΝΟΣ

After some brief discussion of the course's scope and aims, we begun with the definition of a distance function (metric) w.r.t. a non empty set of reference as a real function defined on the product of this set with itself that satisfies positivity, separation, symmetry and triangle inequality. The example of the discrete metric showed that any such set bears at least one such function, and further examples implied that more than one metrics can exist, possibly inside structured families, some o

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Friday, May 29, 2020 at 3:14 AM
- written by user ΑΡΒΑΝΙΤΗΣ ΣΤΥΛΙΑΝΟΣ

We concluded the course with applications of the BFPT; those involve the Bellman equation and the Theorem of Picard-Lindelof.
 
You can find the lectures' whiteboards here and here. Notes for the above can be found here
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Friday, May 22, 2020 at 9:33 PM
- written by user ΑΡΒΑΝΙΤΗΣ ΣΤΥΛΙΑΝΟΣ

We examined a stronger notion of continuity in metric spaces, namely Lipschitz continuity. We proceeded with the examination of the Banach Fixed Point Theorem after having introduced some general aspects of fixed point theory.
 
You can find the lectures' whiteboards here and here. Notes for the above can be found here and here
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Friday, May 15, 2020 at 1:59 PM
- written by user ΑΡΒΑΝΙΤΗΣ ΣΤΥΛΙΑΝΟΣ

We examined the notion of continuity of functions between metric spaces. We then focused on our first major application: approximation of optimization problems. We then begun the examination of further non topological notions concerning metric spaces and functions between them: completeness and Lipschitz continuity

You can find the lectures' whiteboards here and here. Notes for the above can be found here, here and here.  

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Saturday, May 9, 2020 at 3:20 AM
- written by user ΑΡΒΑΝΙΤΗΣ ΣΤΥΛΙΑΝΟΣ

We continued with issues of (sequential) convergence in metric spaces.

You can find the lecture's whiteboards here. Notes for the above can be found here.  

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Friday, May 1, 2020 at 9:18 PM
- written by user ΑΡΒΑΝΙΤΗΣ ΣΤΥΛΙΑΝΟΣ

We have examined further details on total boundness among others involving our discriptive examination of the notion of covering numbers. We have pointed out to the usefulness of the above in applications involving issues of convergence in metric spaces, or properties of stochastic properties. We have begun our examination of topological notions in metric spaces with the notion of (sequential) convergence.

The lecture's whiteboards can be found here. Notes on the above can be found here, and her

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