Banach algebrasSee also what's at Wikipedia, your library, or elsewhere.
Broader terms:Narrower terms:Used for: Algebras, Banach
 Banach rings
 Metric rings
 Normed rings

Filed under: Banach modules (Algebra)Filed under: Harmonic analysis
Filed under: Lamé's functionsFiled under: Spherical harmonics
Filed under: Ausdehnungslehre
Items below (if any) are from related and broader terms.
Filed under: Banach spaces
Filed under: Hilbert space
Filed under: Spectral theory (Mathematics)
Filed under: Operator algebras Operator Algebras and Quantum Statistical Mechanics, by Ola Bratteli and Derek W. Robinson
Filed under: Noncommutative differential geometry 