Fermat Prime
A Fermat Number 
which is Prime.
- Blaschke's Theorem
- Blecksmith-Brillhart-Gerst Theorem
- Blichfeldt's Lemma
- Blichfeldt's Theorem
- BLM/Ho Polynomial
- Bloch Constant
- Bloch-Landau Constant
- Block
- Block Design
- Block Growth
- Block Matrix
- Block (Set)
- Blow-Up
- Blue-Empty Coloring
- Blue-Empty Graph
- Board
- Boatman's Knot
- Bochner Identity
- Bochner's Theorem
- Bode's Rule
- Bogdanov Map
- Bogomolov-Miyaoka-Yau Inequality
- Bohemian Dome
- Bohr-Favard Inequalities
- Bolyai-Gerwein Theorem