Cool jazz is a modern jazz genre which emerged in the United States after World War II and shortly after the emergence of bop. It is distinguished from bop by virtue of its slower rhythms and less complex arrangements; hence it conveys a relaxed and sophisticated or "cool" sound. Cool jazz emerged in the late 1940s through at least two streams: the innovation of a mellower style of bop (e.g. Miles Davis and Gerry Mulligan), or alternatively the further development of elements of swing into a small-group setting (e.g. Lee Konitz, Lennie Tristano and the work of Brubeck and Desmond). A substantial subset of cool jazz adherents emerged in the 1940s and 1950s in California (e.g. Shorty Rogers, Chet Baker, and Stan Getz), whose recorded output is often referred to as West Coast Jazz but which in style is largely indistinguishable from cool jazz.