Question about Properties of Relations

[Learning_Math]

1. The question is: P on the set, A, of all people, where xPy means x is a parent of y.

Homework Equations

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3. Attempts at a Solution Here is where I am confused. Reflexivity is defined by aRa. So I am unclear what to do with more than one variable. So in this question, do I examine if xRx? That is to say is x a parent of x? If that is the case, then the answer is clearly no. I am just unsure of how to deal with reflexivity.

I am ok with symmetry and transitivity.

 

[Mark44]

Can x be the parent of x? IOW, can someone be his or her own parent?

 

[Learning_Math]

Okay, so am I correct in what to do with reflexivity in this question? It is obviously absurd that x can be the parent of x. Where I am unclear is if that is the question I need to be asking vis-a-vis reflexivity.

 

[Mark44]

I thought I was pretty clear - the relation P is not reflexive.

 

[Learning_Math]

I thought I was pretty clear - the relation P is not reflexive.

You were pretty clear. I am just at the very end of my proof writing class, and it has me pretty jumpy. Thanks for your help.