outer measure
m(⌀) = 0;
m is monotonic: if A ⊆ B, then m(A) ≤ m(B);
m is countably subadditive: 
.
.Given an outer measure m, a set E is called Carathéodory measurable if
for all subsets A of X. The Carathéodory measurable sets form a sigma algebra on which m is a measure.
- Fibonacci
- Fibonacci multiplication
- Fibonacci number
- fibre
- fictitious force
- field
- field extension
- field of force
- field of fractions
- Fields Medal
- figurate numbers
- figure
- financial mathematics
- finite
- finite differences
- finite element method
- finite field
- finite intersection property
- finitely generated
- finite population correction
- finite‐dimensional
- finitism
- first derivative
- first fundamental form
- first isomorphism theorem