Basic Set Theory: Determining Relations: Reflexive, Symmetric, Transitive

AI Thread Summary
The discussion focuses on determining the properties of a specific relation in set theory, including whether it is reflexive, symmetric, transitive, and others. The relation given is identified as nonreflexive, nonsymmetric, and transitive, but there is uncertainty regarding its classification as asymmetric or antisymmetric due to the presence of the pair (e,e). The definitions of asymmetric and antisymmetric are clarified, with asymmetric indicating that if x relates to y, then y cannot relate back to x, while antisymmetric states that if both x relates to y and y relates to x, then x must equal y. The participant seeks further understanding of these concepts in the context of their homework. Overall, the discussion emphasizes the nuances of set relations and their classifications.
Bob4040
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I am taking a philosophy course that covers basic set theory as part of the introduction. I’m not sure in which section of the forum set theory should be, but I think this is the right place.

Homework Statement



For each of the following relations, indicate whether it is Reflexive, Nonreflexive, Irrelfexive, Symmetric, Nonsymmetric, Asymmetric, Antisymmetric, Transitive, Nontransitive, and Intransitive.

9) {(b,d), (a,c), (d,c), (e,e), (b,c)} on the set {a,b,c,d,e}.

Homework Equations


The Attempt at a Solution



I believe they are Nonreflexive, nonsymmetric, and transitive.

I do not know if they are Asymmetric or Antisymmetric because I do not know how to deal with (e,e).
 
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You are correct that this relation is not symmetric because it contains (a, c) but not (c, a). It is not reflexive because it does not contain (a, a), (b, b), and (c, c). It is transitive because the only pairs of the form '(x, y), (y, z)' are (b, d) and (d, c) and it does contain (b, c). What is the difference between 'asymmetric' and 'antisymmetric'?
 
HallsofIvy said:
What is the difference between 'asymmetric' and 'antisymmetric'?


Asymmetric: xRy \Rightarrow \neg (yRx)

Antisymmetric: xRy \wedge yRx \Rightarrow x=y
 
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