Editing Set Theory (section)

== <span style="color: #FFFFFF;">Remembering</span> ==
* '''Set''' — A collection of distinct objects (e.g., $\{1, 2, 3\}$).
* '''Element ($\in$)''' — An object that is a member of a set.
* '''Subset ($\subseteq$)''' — A set where every element is also in another set.
* '''Empty Set ($\emptyset$)''' — A set containing no elements.
* '''Union ($\cup$)''' — Combining all elements of two sets.
* '''Intersection ($\cap$)''' — Only the elements that two sets have in common.
* '''Cardinality''' — The "Size" of a set (the number of elements it contains).
* '''Power Set''' — The set of all possible subsets of a set.
* '''Infinite Set''' — A set with an unlimited number of elements (e.g., the set of all integers).
* '''Countable Infinity ($\aleph_0$)''' — The "Smallest" infinity; a set that can be put into a 1-to-1 list with the counting numbers (1, 2, 3...).
* '''Uncountable Infinity''' — A "Larger" infinity, like the set of all decimal numbers between 0 and 1.
* '''Venn Diagram''' — A visual way to show the relationships between sets.
* '''Ordered Pair''' — A set of two elements where the order matters (e.g., $(x, y)$).
* '''Axiom of Choice''' — A controversial axiom that says you can always pick one element from each of an infinite collection of sets.
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