An involutive Banach algebra is a Banach algebra 
which is an involutive algebra and 
for all 
.
Involutive Banach Algebra
This entry contributed by Mohammad Sal Moslehian
Explore with Wolfram|Alpha
References
Bonsall, F. F. and Duncan, J. Complete Normed Algebras. New York: Springer-Verlag, 1973.Referenced on Wolfram|Alpha
Involutive Banach AlgebraCite this as:
Moslehian, Mohammad Sal. "Involutive Banach Algebra." From MathWorld--A Wolfram Web Resource, created by Eric W. Weisstein. https://mathworld.wolfram.com/InvolutiveBanachAlgebra.html