in this short note, we have given a short proof for the existence of the haar measure on commutative locally compact hypergroups based on functional analysis methods by using markov-kakutani fixed point theorem.

where d×x denotes a Haar measure on G. Up to constants, for (additive) Haar measure dx on A, d×x = dx/|detx|. For brevity, write |x| for |detx| when possible. [0.1] Convergence The integral defining us converges absolutely in Re(s) > n− 1: Recall the Iwasawa decomposition G = P ·K with P the parabolic subgroup of upper-triangular matrices. Since K is open in G, Haar measure on G restricted to K...