MATH 320 - Set Theory - Lecture 1.2

Course: MATH 320 - Set Theory
Instructor: Asst. Prof. Burak KAYA

Middle East Technical University

[timotejsinkovic]

I think that how the intersection is defined here is incorrect, if we choose a _z_ that does not belong to _x_ and then choose _y_ belonging to that _z_ (or even _y_ not belonging to _z_ ) the formula will turn out to be true yet _y_ is not even a member of member of _x_ . I might have this wrong though, since first order logic is pretty hard for me to understand

[LaureanoLuna]

No point in adding constants as parameters to phi(x); phi(x) can already have them. The formula in parentheses at 45:12 should be a conditional, not a biconditional.

[vikasshukla]

Isn't an empty set in the collection of R? Empty set belongs to itself and also doesn't belongs to itself am I right? I am a bit confused about this Russell paradox.

[xcl]

37:40: wait, { and } are not allowed in formula

[xcl]

he use first order logic a lot, the Jedi won't be happy