olemus
matemaatilise loogika haru, uurib hulki elemendiks olemise seose ∈ omaduste kaudu:
- naiivses hulgateoorias on hulk suvaliste objektide kogum
- aksiomaatilises hulgateoorias tuleb mingi omadusega hulga olemasolu formaalselt tõestada
=
a branch of mathematical logic, investigates sets through the properties of the relationship ∈ of being an element of a set :
- in naive set theory, a set is a collection of arbitrary objects
- in axiomatic set theory, the existence of a set with a certain property must be formally proven

ülevaateid
https://en.wikipedia.org/wiki/Set_theory

https://www.bu.edu/lernet/artemis/years/2011/slides/settheory.pdf

http://www.math.toronto.edu/weiss/set_theory.pdf

https://www.cl.cam.ac.uk/~gw104/STfCS2010.pdf

https://www.mbacrystalball.com/blog/2015/10/09/set-theory-tutorial/