Step variety: Difference between revisions

Inthar (talk | contribs)
m Inthar moved page Arity to Step variety over redirect
Fredg999 (talk | contribs)
Misc. edits in lead section and etymology section
Line 1: Line 1:
An ''n'''''-ary scale''' is a scale with exactly ''n'' distinct step sizes; a scale's '''step variety''' or '''arity''' is the number of distinct step sizes it has. '''Unary''', '''binary''', '''ternary''', and '''quaternary''' scales are scales with exactly 1, 2, 3, and 4 step sizes, respectively.
The '''step variety''' (or '''arity''') of a [[scale]] is the number of distinct [[step]] sizes it has. '''Unary''', '''binary''', '''ternary''', and '''quaternary''' scales are scales with exactly 1, 2, 3, and 4 step sizes, respectively. An ''n'''''-ary scale''' is a scale with exactly ''n'' distinct step sizes.


Unary scales are [[equal tuning]]s. The class of binary scales consists of all [[MOS]] scales and every alteration-by-permutation of a MOS scale, but do not include altered MOS scales such as the harmonic minor scale, msmmsLs, which gain additional step sizes from the alteration. Ternary scales are much less well-understood than binary ones, but one well-studied type of ternary scales is the class of [[generator-offset]] scales. Most known facts about ternary scales on the wiki can be found on the page [[rank-3 scale]] (which is mostly about specifically ternary scales).
Unary scales are [[equal tuning]]s. The class of binary scales consists of all [[MOS scale]]s and every alteration-by-permutation of an MOS scale, but do not include [[altered MOS scale]]s such as the harmonic minor scale (abstract [[step pattern]]: MsMMsLs), which gain additional step sizes from the alteration. Ternary scales are much less well-understood than binary ones, but one well-studied type of ternary scales is the class of [[generator-offset]] scales. Most known facts about ternary scales on the wiki can be found on the page [[rank-3 scale]] (which is mostly about specifically ternary scales).
== History of the term ==
The terms ''binary'' and ''ternary'' are already used in some academic literature in reference to words over an alphabet, in particular to circular words that represent abstract scales; see e.g. Bulgakova, Buzhinsky and Goncharov (2023), "[https://www.sciencedirect.com/science/article/pii/S0304397522006417 On balanced and abelian properties of circular words over a ternary alphabet]". The use of the term ''arity'' borrows an {{w|Arity|existing technical term}} and generalizes from this use of ''binary'', ''ternary'', and ''n-ary'' to refer to the number of letters in an alphabet in combinatorics on words; combinatorics-on-words literature often instead uses "word on ''n'' letters" or "alphabet with ''n'' letters" in the arbitrary-''n'' case.


''Step variety'', coined by [[User:fredg999]], is in analogy with ''[[interval variety]]'' for the number of distinct interval sizes in each [[interval class]].
== Etymology ==
The terms ''binary'' and ''ternary'' are already used in some academic literature in reference to [[word]]s over an alphabet, in particular to circular words that represent abstract scales; see e.g. Bulgakova, Buzhinsky and Goncharov (2023), "[https://www.sciencedirect.com/science/article/pii/S0304397522006417 On balanced and abelian properties of circular words over a ternary alphabet]". The use of the term ''arity'' borrows an {{w|Arity|existing technical term}} and generalizes from this use of ''binary'', ''ternary'', and ''n-ary'' to refer to the number of letters in an alphabet in combinatorics on words; combinatorics-on-words literature often instead uses "word on ''n'' letters" or "alphabet with ''n'' letters" in the arbitrary-''n'' case.
 
The term ''step variety'', coined by [[Frédéric Gagné]], is in analogy with ''[[interval variety]]'' for the number of distinct interval sizes in each [[interval class]].


== Difference from scale rank ==
== Difference from scale rank ==