3645/3584: Difference between revisions

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m add etymology section, propose alternate name that feels less awkward than current name, link, note connection to septimal meantone
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{{Infobox interval
{{Infobox interval
| Name = tritonic diesis{{idiosyncratic}}, schismean comma{{idiosyncratic}}
| Name = aberdiesis{{idiosyncratic}}, schismean comma{{idiosyncratic}}
| Color name = Lry-2, Laruyo negative 2nd
| Color name = Lry-2, Laruyo negative 2nd
| Comma = yes
| Comma = yes
}}
}}


The '''tritonic diesis'''{{idiosyncratic}} or '''schismean comma'''{{idiosyncratic}} ([[monzo]]: {{monzo|-9 6 1 -1}}, [[ratio]]: 3645/3584) is a [[small comma|small]] [[7-limit]] [[comma]] measuring about 29.2 [[cent]]s.
The '''aberdiesis'''{{idiosyncratic}} or '''schismean comma'''{{idiosyncratic}} ([[monzo]]: {{monzo|-9 6 1 -1}}, [[ratio]]: 3645/3584) is a [[small comma|small]] [[7-limit]] [[comma]] measuring about 29.2 [[cent]]s. It is the difference between three major whole tones and a small septimal tritone, or in other words, ([[9/8]])<sup>3</sup>/([[7/5]]).  


It is the difference between three major whole tones and a small septimal tritone, or in other words, ([[9/8]])<sup>3</sup>/([[7/5]]).
It factors into simpler commas as ([[81/80]])⋅([[225/224]]) or ([[126/125]])⋅(225/224)<sup>2</sup>. In the [[11-limit]] it further factors into ([[99/98]])⋅([[2835/2816]]), ([[385/384]])⋅([[2187/2156]]), and ([[540/539]])⋅([[2079/2048]]).  


== Temperaments ==
== Temperaments ==
It is most notably and characteristically tempered out in [[septimal meantone]], where 7/5 is an augmented fourth, as the flat fifth of meantone helps motivate this equivalence.
[[Tempering out]] this comma leads to the rank-3 [[miscellaneous 7-limit temperaments #Aberdietic|aberdietic]] temperament. It is most notably and characteristically tempered out in [[septimal meantone]], where 7/5 is an augmented fourth, as the flat fifth of meantone helps motivate this equivalence. Other rank-2 temperaments which temper out this comma include [[schism]] and [[pycnic]].
 
Tempering out this comma leads to the rank-3 [[Miscellaneous 7-limit temperaments #Schismean|schismean]] temperament. Other rank-2 temperaments which temper out this comma include [[schism]] and [[pycnic]].


== Etymology ==
== Etymology ==
The name ''schismean'' was given by [[User:Xenllium|Xenllium]] in 2022, most likely as a contraction of [[schism]] and [[meantone]]. The name ''tritonic diesis'' was given later in 2026 by the observation of [[User:Godtone|Godtone]] that it fit a general algorithmic definition discussed in [[Diesis#Generalization]], combined with the observation that the ''septimal tritonic diesis'' of (10/7)/(7/5) = [[50/49]] seemed to suggest the existence of a ''tritonic diesis'' with a focus on the ''tritone'' part as contrasted to the ''septimal'' part, hence the expression of it as the amount by which the "literal" tritone [[729/512|(9/8)<sup>3</sup>]] exceeds the LCJI tritone [[7/5]].
The name ''schismean'' was given by [[Xenllium]] in 2022, most likely as a contraction of [[schism]] and [[meantone]]. The name ''aberdiesis'' was given later in 2026 by the observation of [[Fumica]] to observe a pun with the closely-related comma (10/7)/(9/8)<sup>3</sup> = [[64/63|S8]]/[[81/80|S9]] = [[5120/5103]], the aberschisma, in light of {{u|Godtone}}'s observation that it behaves in almost all ways like a diesis according to a specific intuitively-motivated definition discussed in [[Diesis #Generalization]].


[[Category:Commas named by combining multiple temperament names]]
[[Category:Commas named by combining multiple temperament names]]

Latest revision as of 11:00, 30 July 2026

Interval information
Ratio 3645/3584
Factorization 2-9 × 36 × 5 × 7-1
Monzo [-9 6 1 -1
Size in cents 29.21781¢
Names aberdiesis[idiosyncratic term],
schismean comma[idiosyncratic term]
Color name Lry-2, Laruyo negative 2nd
FJS name [math]\displaystyle{ \text{d}{-2}^{5}_{7} }[/math]
Special properties reduced
Tenney norm (log2 nd) 23.6391
Weil norm (log2 max(n, d)) 23.6634
Wilson norm (sopfr(nd)) 48
Comma size small
Open this interval in xen-calc

The aberdiesis[idiosyncratic term] or schismean comma[idiosyncratic term] (monzo: [-9 6 1 -1, ratio: 3645/3584) is a small 7-limit comma measuring about 29.2 cents. It is the difference between three major whole tones and a small septimal tritone, or in other words, (9/8)3/(7/5).

It factors into simpler commas as (81/80)⋅(225/224) or (126/125)⋅(225/224)2. In the 11-limit it further factors into (99/98)⋅(2835/2816), (385/384)⋅(2187/2156), and (540/539)⋅(2079/2048).

Temperaments

Tempering out this comma leads to the rank-3 aberdietic temperament. It is most notably and characteristically tempered out in septimal meantone, where 7/5 is an augmented fourth, as the flat fifth of meantone helps motivate this equivalence. Other rank-2 temperaments which temper out this comma include schism and pycnic.

Etymology

The name schismean was given by Xenllium in 2022, most likely as a contraction of schism and meantone. The name aberdiesis was given later in 2026 by the observation of Fumica to observe a pun with the closely-related comma (10/7)/(9/8)3 = S8/S9 = 5120/5103, the aberschisma, in light of Godtone's observation that it behaves in almost all ways like a diesis according to a specific intuitively-motivated definition discussed in Diesis #Generalization.