New posts in Elementary Set Theory

How is $P(A^c \cap B^c)$ the same as $1-P(A \cup B)$?

What does "relation induced by a partition" mean?

What's the matter of Cantor's diagonal argument in binary system？

Sets symmetric difference, proving elements belonging to $A, B$ or $C$

Proof verification (sets & logic)

Prove that "injective function $f:X\to Y$ exists" and "surjective function $g:Y\to X$ exists" is logically equivalent.

Is it possible to use set-builder notation to define the reals using the complex numbers?

How to prove $\forall k \exists y \forall x (x < y \Leftrightarrow \forall n (n < x \Rightarrow n < k))$?

How to show the cardinality $0$ is less than the cardinality $1$

Proving $A \subset B \implies A \cup B = B$