Denoting the Largest Member of a Set: Symbols & Techniques

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Discussion Overview

The discussion revolves around the notation and concepts related to denoting the largest member of a set, particularly in the context of mathematics. Participants explore various symbols and definitions, including maximums and supremums, and their implications in both finite and infinite sets.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant inquires about the appropriate notation for denoting the largest member of a set, specifically asking about symbols used.
  • Another participant suggests using the notation max(A) as a formal way to express the largest member of a set.
  • A question is raised regarding the distinction between maximums and least upper bounds (supremums), with a request for clarification on their definitions.
  • It is noted that the maximum of a set must be a member of that set, with an example provided of a set that has a supremum but no maximum.
  • One participant asserts that for infinite sets, there may not be a greatest element even if the set is bounded above, emphasizing that the supremum is the smallest upper bound and is equal to the maximum only if it is an element of the set.
  • It is stated that any finite set must have a maximum.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between maximums and supremums, with some agreeing on definitions while others seek clarification. The discussion remains unresolved regarding the nuances between these concepts.

Contextual Notes

Participants highlight limitations in definitions and the conditions under which maximums and supremums apply, particularly in the context of finite versus infinite sets.

bomba923
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Let's say I have a set {A}. How do I denote the largest member of that set?
For example, let's say I have a solution set of discrete values. How do I denote the largest solution?

Basically, with any set, how do I denote the largest member of that set? What symbol/s do I use !?
 
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What's wrong with something like [tex]max(A)[/tex]??
 
That is the formal/accepted way of expressing it (the largest member of a set), right?
 
Do maximums differ from least upper bounds (supremums)? The definitions I found didn't clear this up. Edit: Eh, because I was going to say supremum.
 
AFAIK, the maximum of a set must necessarily be a member of the set as well. So for example, {1 - 1/n; n a natural} has a supremum, but no maximum.
 
Muzza is absolutely correct.

given a set (presumably of real numbers) there is no reason for that set to even have a greatest element, even if it is bounded above (ie all elements are less than some constant K). The sup is the smallest such K that bounds them above, and this is the max if and only if K is an element of the set.

Note, that this only applies to infinite sets. Any finite set of points must have a maxmimum.
 

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