 The sequent calculus presented in Manzano (1996: 240–257) is the many-sorted extension of the one in Ebbinghaus, Flum, and Thomas (1984). Hao Wang (1952: 106), one of the pioneering logicians working on many-sorted logic, already introduced an axiomatic calculus for this logic in his seminal work (see the  supplement on early history  for more information).