Is the Definition of a Topological Space Paradoxical?

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Discussion Overview

The discussion revolves around the definition of a topological space, exploring its implications and addressing perceived paradoxes. Participants examine the nature of open and closed sets, the distinction between algebraic and geometric concepts in topology, and the foundational aspects of set theory as it relates to topology.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions the inclusion of the set X in the collection T, suggesting it resembles a paradox similar to Russell's paradox, and seeks clarification on the interpretation of the axiom.
  • Another participant clarifies that T is a subset of the power set of X, which includes all subsets of X, thus allowing X to be a member of T.
  • There is a discussion on the nature of topological spaces being more algebraic than geometric, with some participants arguing that topology relies on set-theoretic definitions rather than algebraic properties.
  • One participant expresses confusion about the distinction between open and closed sets, proposing that the difference lies in the boundary conditions of the intervals.
  • Another participant explains that a set is open if it is in the topology and that a set is closed if its complement is open, emphasizing the flexibility in defining open sets.
  • There is a clarification regarding the specific intervals (0,1) and [0,1], with an explanation of why (0,1) is open and [0,1] is not, based on the existence of neighborhoods around points within those sets.
  • A participant raises a question about the necessity of having only open sets in a topology, hinting at the rules governing set behavior.

Areas of Agreement / Disagreement

Participants express varying interpretations of the definition of a topological space and its implications. There is no consensus on the nature of open and closed sets, as well as the algebraic versus geometric characterization of topology.

Contextual Notes

Some participants acknowledge limitations in their understanding of set theory and topology, and there are unresolved questions regarding the definitions and properties of open and closed sets.

  • #31
I don't think that Differential Geometry requires a strong background in topology, but my experience with Differential Geometry hasn't exactly been the best, so someone else should probably comment on that.

http://math.ucr.edu/home/baez/

might help with your quest for information.
 
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  • #32
T is not a subset of X. T is a collection of subsets of X. In other words, T is a set of sets. Your first reply said this in a fancy way, by stating that T is a subset of the power set of X. To be a topology, T must contain at least two elements: X itself, and the empty set. If T contains only these two sets, it is called the indiscreet topology
for X. If T contains all subsets of X, i.e., the entire power set, then T is called the
discreet topology. Interesting topologies associated with X are usually between these two extremes.
 
  • #33
Just learn differential geometry and tensor calculus, and you'll be set for a good into to GR. There are many good books on the topic; I like one called "A Short Course on General Relativity" by Nightingale.

- Warren
 
  • #34
this discussion persuades me that the art of reading books is hopelessly lost. anyone who read even a few pages of a mediocre book on topology would not have any of these questions.

web based learning is obviously a satanic invention of the powers of ignorance, superstition, and darkness!
 

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