  We study the so-called multi-mixed fractional Brownian motions (mmfBm) and
multi-mixed fractional Ornstein--Ulhenbeck (mmfOU) processes. These processes
are constructed by mixing by superimposing (infinitely many) independent
fractional Brownian motions (fBm) and fractional Ornstein--Uhlenbeck processes
(fOU), respectively. We prove their existence as $L^2$ processes and study
their path properties, viz. long-range and short-range dependence, H\"older
continuity, $p$-variation, and conditional full support.
