Musical note commonly), a double sharp sign on a key signature with a single sharp indicates only a double sharp, not a triple sharp. Assuming enharmonicity, many accidentals will create equivalences between pitches that are written differently. For instance, raising the note B to B is equal to the note C. Assuming all such equivalences, the complete chromatic scale adds five additional pitch classes to the original seven lettered notes for a total of 12 (the 13th note completing the octave), each separated by a half-step. Notes that belong to the diatonic scale relevant in the context are sometimes called "diatonic notes";
Transposition (music) Thus the set ("A") consisting of 0–1–2 transposed by 5 semitones is 5–6–7 (T("A")) since , , and . There are two different kinds of transposition, depending on whether one is measuring intervals according to the chromatic scale or some other scale. In chromatic transposition one shifts every pitch in a collection of notes by a fixed number of semitones. For instance, if one transposes the pitches C–E–G upwards by four semitones, one obtains the pitches E–G–B. In scalar transposition one shifts every pitch in a collection by a fixed number of scale steps relative to some scale. For example,