Operations on MOSes: Difference between revisions

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== Sisterization ==
== Sisterization ==
'''Sisterization''' is the operation of taking a MOS pattern xL ys and reversing the roles of large and small steps, thus creating a yL xs pattern, called the ''sister'' of xL ys. Inverted MOS patterns are often denoted with the prefix ''anti-''.
'''Sisterization''' is the operation of taking a MOS pattern xL ys and reversing the roles of large and small steps, thus creating a yL xs pattern, called the ''sister'' of xL ys. It is called thus because they share the same MOS as a subset (for example, [[5L 2s]] and [[2L 5s]] both have [[2L 3s]] subsets), which is the parent on the tree of MOS patterns (closely related to the Stern-Brocot tree). A sister of a MOS pattern are often denoted with the prefix ''anti-''.


If xL ys has a generator range between a\x and b\(x+y) (it always holds that a < b), then its inversion yL xs has a generator range between b\(x+y) and (b-a)\y.
If xL ys has a generator range between a\x and b\(x+y) (it always holds that a < b), then its sister yL xs has a generator range between b\(x+y) and (b-a)\y.


Examples:
Examples:
* [[2L 5s]] is the sister of [[5L 2s]] (anti-diatonic)
* [[2L 5s]] is the sister of [[5L 2s]] (anti-diatonic)
* [[3L 5s]] is the sister [[5L 3s]] (anti-oneirotonic)
* [[3L 5s]] is the sister [[5L 3s]] (anti-oneirotonic)
== Neutralization ==
== Neutralization ==
'''Neutralization''' is the operation of taking a MOS pattern and creating a new MOS pattern with the same number of notes, but with some of the steps replaced with what would be "neutral seconds" according to the original MOS pattern.
'''Neutralization''' is the operation of taking a MOS pattern and creating a new MOS pattern with the same number of notes, but with some of the steps replaced with what would be "neutral seconds" according to the original MOS pattern.