S-expression: Difference between revisions
m added a glossary of proposed convenient shorthand terms, most of which used in this article for explaining concepts |
|||
| Line 17: | Line 17: | ||
== Sk/S(k+1) (ultraparticulars) == | == Sk/S(k+1) (ultraparticulars) == | ||
Note that | |||
Note that tempering any two consecutive square-particulars will naturally imply tempering the ultraparticular between them (meaning they are very common implicit commas), and that tempering any two consecutive ultraparticulars will imply tempering the [[#Sk/S(k+2) (semiparticulars)|semiparticular]] which is their sum/product. An arithmetic of rather interesting commas whose elements are square-particulars exists. This arithmetic can be described compactly with '''S-expressions''', which is to say, expressions composed of square superparticulars multiplied and divided together, using the Sk notation to achieve that compactness.) | |||
{| class="wikitable center-all | {| class="wikitable center-all | ||
| Line 85: | Line 86: | ||
| [[24576/24565]] | | [[24576/24565]] | ||
|} | |} | ||
(Note that while a lot of these have pages, not all of them do, although that doesn't mean they shouldn't.) | |||
Note from this table how the shorthand becomes increasingly convenient higher up the series, where (preferably [[consistent]]) temperaments that temper out the ultraparticular but neither of the superparticulars which it is a difference between are of increasing precision. Note also how every three superparticulars the interval divided into three equal parts simplifies to a superparticular. This happens for S(3k+1)/S(3k+2) for a positive integer k, because then the superparticular can be expressed as: | Note from this table how the shorthand becomes increasingly convenient higher up the series, where (preferably [[consistent]]) temperaments that temper out the ultraparticular but neither of the superparticulars which it is a difference between are of increasing precision. Note also how every three superparticulars the interval divided into three equal parts simplifies to a superparticular. This happens for S(3k+1)/S(3k+2) for a positive integer k, because then the superparticular can be expressed as: | ||
| Line 198: | Line 202: | ||
| [[4375/4374]] | | [[4375/4374]] | ||
|} | |} | ||
(Note that while a lot of these have pages, not all of them do, although that doesn't mean they shouldn't.) | |||
== Glossary == | |||
'''Superparticular''': The interval/comma between two consecutive harmonics. See [[superparticular]]. | |||
These are of the form (k+1)/k. | |||
'''Square-particular''': A superparticular interval/comma whose numerator is a square number. A shorthand (nick)name for square superparticular. | |||
These are of the form k<sup>2</sup>/(k<sup>2</sup> - 1) = Sk. | |||
'''Odd-particular''': An interval/comma between two consecutive odd harmonics. The odd analogue of superparticular. | |||
These are of the form (2k+1)/(2k-1). | |||
'''Throdd-particular''': An interval/comma between two harmonics 3 apart which is not superparticular. | |||
These are of the form (3k+1)/(3k) or (3k+2)/(3k+1). | |||
'''Quodd-particular''': An interval/comma between two harmonics 4 apart which is not superparticular or odd-particular. | |||
These are of the form (4k+1)/(4k-1) and (4k+3)/(4k+1). | |||
'''Ultraparticular''': An interval/comma which is the ratio of two consecutive square-particulars. | |||
These are of the form Sk/S(k+1). | |||
'''Semiparticular''': A superparticular or odd-particular interval/comma which is the ratio between two adjacent-to-adjacent square-particulars, which is to say: | |||
These are of the form Sk/S(k+2). | |||
'''S-expression''': An expression using the Sk shorthand notation corresponding strictly to multiplying and dividing only (arbitrary) square-particulars. S-expressions include singular square superparticulars and expressions for other superparticulars in terms of square superparticulars. | |||
'''Metaparticulars''': A suggested name for the general class of commas describable by S-expressions. | |||
== Mathematical derivation == | == Mathematical derivation == | ||
| Line 271: | Line 311: | ||
:: = ( 2m + 2(3a) + 1 )/( 2m + 2(3a) - 1 ) | :: = ( 2m + 2(3a) + 1 )/( 2m + 2(3a) - 1 ) | ||
:: ...which is of the form ( | :: ...which is of the form (2x + 1)/(2x - 1) meaning it is odd-particular. | ||
In conclusion: Sk/S(k+2) is superparticular for k =/= 3 (mod 4) and is odd-particular when k = 3 (mod 4). | In conclusion: Sk/S(k+2) is superparticular for k =/= 3 (mod 4) and is odd-particular when k = 3 (mod 4). | ||