User:VectorGraphics/REXICS

REXICS is a contrarian interval classification system. For any JI interval that is given a name corresponding to a diatonic interval category, the REXICS classification classifies it as the other corresponding enharmonic interval category.

Unison <-> Diminished second

Augmented unison <-> Minor second

Diminished third <-> Major second

Minor third <-> Augmented second

Major third <-> Diminished fourth

Augmented third <-> Perfect fourth

Diminished fifth <-> Augmented fourth

And octave complements.

Usually, the REXICS classification doesn't have any justification behind it, but in some cases, for example when an article randomly

claims an interval belongs to one category or the other without any theory behind it, or without any reason to make the distinction at all outside of the context of some kind of scale (which JI articles for >3 limits are in general), it's just as reasonable as the article's given classification. This is especially common with diatonic and chromatic semitones (i.e. augmented unisons and minor seconds).