From the three rather spartan axioms of set-theoretic probability theory a whole world of results follow by proof of lemmas of increasing complexity. To help along the way we can now steal some of the basic findings of set theory. I won't go into detail on them but take them as read.
- $\exists \emptyset$
- $\exists E$, the sample space
- Set sizes can be finite, countably infinite and uncountably infinite
- All subsets of the integers are at most countably infinite
- The set of real numbers is uncountably infinite
- The set of real numbers in the $\left[0,1\right]$ interval is also uncountably infinite
- $A\cup A = A$
- $A \cup \emptyset = A$
- $A \cup E = E$
- $A \cup B = B \cup A$
- $A \cup B \cup C = A \cup (B \cup C) = (A \cup B) \cup C$
- $A \cap \emptyset = A$
- $A \cap A = A$
- $A \cap E = E$
- $A \cap B = B \cap A$
- $A \cap B \cap C = A \cap (B \cap C) = (A \cap B) \cap C$
- $(A^c)^c=A$
- $\emptyset^c=E$
- $S^c=\emptyset$
- $A \cup A^c = S$
- $A \cap A^c = \emptyset$
No comments:
Post a Comment