Examples of ordered topology on R x R

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Discussion Overview

The discussion revolves around the concepts of ordered topology and subspace topology, specifically focusing on examples involving the spaces {1} x (1, 2] and {1, 2} x Z_+. Participants explore how to define bases for these topologies and the implications of different ordering methods.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant seeks to understand how to express the ordered topology for the space {1} x (1, 2] and how to write a basis for {1, 2} x Z_+.
  • Another participant inquires about the specific order intended for the second space, suggesting that the choice of order is crucial.
  • A participant proposes using dictionary order for the spaces, indicating that (1, 2) is less than (2, 2) and (1, 3), while expressing uncertainty about other possible orders.
  • There is a clarification that the order topology is generated by intervals, prompting a request for descriptions of the intervals in the discussed spaces.
  • A participant describes the intervals for {1} x (1, 2] as half-open intervals and discusses the basis for {1, 2} x Z_+, suggesting that multiple order topologies can be defined on a set.

Areas of Agreement / Disagreement

The discussion reflects a lack of consensus on the specific orders that can be applied to the spaces and how to define their topologies. Participants express differing views on the nature of the intervals and the bases for the topologies.

Contextual Notes

Participants have not fully resolved the definitions of the intervals or the implications of different ordering methods, leaving some assumptions and mathematical steps unclear.

Pippi
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I am trying to understand the difference between ordered topology and subspace topology. For one, how do I write down ordered topology of the form {1} x (1, 2] ? How do I write down a basis for {1,2} x Z_+ ?
 
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What order are you planning to put on these spaces?? (specifically the second one)
 
I want to put dictionary order on them, so (1, 2) is less than (2, 2) and also less than (1,3). I don't know other orders can be put on them (maybe a metric?) than dictionary order.
 
So, the order topology is by definition generated by intervals. That is

[tex]\{x~\vert~a<x<b\}[/tex]

Can you give a description of the intervals in your two spaces?
 
For the space {1} x (1, 2], the intervals are half open intervals {x | (1, 1] < (1, x] < (1, 2]}. I can also define open intervals {x | (1, 1) < (1, x) < (1, 2)} and a half open interval about {1, (1, 2]}. Both are valid topology.

The space {1,2} x Z_+ contains the set {{1, 1} {1, 2} ... {2, 1}, {2, 2} ... }. Because I can define the basis {x | (x - 1, x + 1), x in Z_+} for space Z_+, the basis are {{1, (x - 1, x+1), {2, (x - 1, x +1)}}. The basis for x = 1 are {1, [1, 2)} and {2, [1, 2)}.

I can't find errors but this is suggesting that I can find many different order topology on a set? Infinitely many? :/.
 

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