Carillon Carillon A carillon ( or ; ) is a musical instrument that is typically housed in the bell tower (belfry) of a church or municipal building. The instrument consists of at least 23 cast bronze, cup-shaped bells, which are played serially to produce a melody, or sounded together to play a chord. A traditional manual carillon is played by striking a keyboard – the stick-like keys of which are called batons – with the fists, and by pressing the keys of a pedal keyboard with the feet. The keys mechanically activate levers and wires that connect to metal clappers that
Partition of a set "coarser" than "α"—if every element of "α" is a subset of some element of "ρ". Informally, this means that "α" is a further fragmentation of "ρ". In that case, it is written that "α" ≤ "ρ". This "finer-than" relation on the set of partitions of "X" is a partial order (so the notation "≤" is appropriate). Each set of elements has a least upper bound and a greatest lower bound, so that it forms a lattice, and more specifically (for partitions of a finite set) it is a geometric lattice. The "partition lattice" of a 4-element set has 15 elements