Orthogonal Basis
A Basis of vectors 
which satisfy
where
, 
are constants (not necessarily equal to 1) and 
is the Kronecker Delta.See also Basis, Orthonormal Basis- Hafner-Sarnak-McCurley Constant
- Hahn-Banach Theorem
- Hailstone Number
- Hairy Ball Theorem
- Half
- Half-Closed Interval
- Half-Normal Distribution
- Half-Open Interval
- Halley's Irrational Formula
- Halley's Method
- Halley's Rational Formula
- Hall-Janko Group
- Halphen Constant
- Halphen's Transformation
- Halting Problem
- Hamiltonian Circuit
- Hamiltonian Cycle
- Hamiltonian Graph
- Hamiltonian Group
- Hamiltonian Map
- Hamiltonian Path
- Hamiltonian System
- Hamilton's Equations
- Hamilton's Rules
- Hammer-Aitoff Equal-Area Projection