UNI_FOUNDATION · Probability · PROB.AXIOMS

Probability spaces basics

Intuition

Understand first, compress later.

Probability quantifies uncertainty. A good model starts with clear possible outcomes and conditions.

Switch representations

Venn diagram|Ω| = 22

universe ΩsetsA ∩ B

The two circles cut the universe into four regions: only A (7), A ∩ B (5), only B (4), and outside both (6). Adding the sizes of A and B counts the shared region twice — which is why it is subtracted once.

Formal view

You can probability spaces basics when you can recognise the underlying objects, select valid rules and check each step for equivalence or logical implication.

Why does it work?

This skill sits on a prerequisite network. If a step is unstable, repair the missing prerequisite instead of merely doing more items of the same type.