Tuning-Math Digests messages 7050 - 7074

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Message: 7050

Date: Thu, 17 Jul 2003 22:02:38

Subject: Re: Obvious things proven

From: Carl Lumma

> Everything you already knew about maximally even scales:
> 
> Maximal Evenness Proofs *

Great stuff, indeed.  That's everything I've ever suspected,
and more.

-Carl


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Message: 7051

Date: Fri, 18 Jul 2003 14:21:15

Subject: Re: Obvious things proven

From: Manuel Op de Coul

Nice indeed. Was the formula p(n) = floor(na/b) proven by Clough and 
Douthett?
Because I remember the definition being in terms of interval sizes.

Manuel


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Message: 7052

Date: Fri, 18 Jul 2003 14:46:13

Subject: Re: Obvious things proven

From: Graham Breed

Manuel Op de Coul wrote:
> Nice indeed. Was the formula p(n) = floor(na/b) proven by Clough and 
> Douthett?
> Because I remember the definition being in terms of interval sizes.

I don't have that paper.  I got it from equation 1.1 in Aytan Agmon's 
1996 one.  He says in Note 17 "In theorems 1.2 and 1.5 Clough and 
Douthett establish that 'being a J-set' (Definition 1.9) is equivalent 
to 'having the property that the spectrum of each dlen is either a 
single integer or two consecutive integers' (Definition 1.7).  Thus 
Clough and Douthett's 'maximal evenness' ... and the present relation 
(1.1) are the same ..."


                    Graham


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Message: 7053

Date: Fri, 18 Jul 2003 16:44:30

Subject: Re: Obvious things proven

From: Manuel Op de Coul

Ah, so Agmon proved it then, good.

Manuel


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Message: 7060

Date: Mon, 21 Jul 2003 18:38:20

Subject: Re: Interesting numerical coincidences (Combinatorics etc)

From: Paul Erlich

--- In tuning-math@xxxxxxxxxxx.xxxx "paulhjelmstad" 

> New finding: C{18,6} Reduces to 493 = 29 X 17 (in terms of unique 
> interval vectors). 17 is on meantone line, but 29 is on schismic. 
So, 
> not along the same line.

what do you mean? look again. the schismic line has a 17 on it as 
close to the ji center as the 17 on the meantone line!


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Message: 7066

Date: Mon, 21 Jul 2003 22:47:15

Subject: Re: Interesting numerical coincidences (Combinatorics etc)

From: Carl Lumma

> This is 89 * 109. I found 89 along "Schismic" in
> Zoomr.gif (hard to read, its really small, and
> doesn't show up in Zooms.gif. I can't find 109. Help!
> Can someone tell me where 109 would show up in a
> taxicab diagram. Thanks!

The diagram appears at different scales here:

Definitions of tuning terms: equal temperament, (c) 1998 by Joe Monzo *

These are not "taxicab" diagrams.  I'm don't know of
any cute name for them.  Maybe Paul E. would care to
coin one.

-Carl


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Message: 7070

Date: Tue, 22 Jul 2003 06:45:49

Subject: Re: Interesting numerical coincidences (Combinatorics etc)

From: Paul Erlich

--- In tuning-math@xxxxxxxxxxx.xxxx "paulhjelmstad" 

> Well good news. C{30,6} reduces to 9,701 sets (based on unique 
> interval vector count). This is 89 * 109. I found 89 along 
"Schismic"
> in Zoomr.gif (hard to read, its really small, and doesn't show up 
in 
> Zooms.gif. I can't find 109. Help! Can someone tell me where 109 
> would show up in a taxicab diagram. Thanks!

a taxicab diagram? why do you call it that?
you should be looking at Definitions of tuning terms: equal temperament, (c) 1998 by Joe Monzo * . . . 
zoom in, zoom out . . .


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Message: 7071

Date: Wed, 23 Jul 2003 11:15:09

Subject: Re: Poor man's harmonic entropy?

From: Carl Lumma

Gene wrote...

>>If x is a positive real number representing an interval, it's 
>>suggested that Pc(x) = exp((log(p/q)-x)^2/2c)) can model the 
>>probability that x is heard as p/q; here c is a parameter. If
>>we take the sum
>>
>>sum q^(-d) Pc(x)
>>
>>over positive rationals p/q, then it isn't hard to see that
>>this converges absolutely for high enough values of d--anything
>>above 2, at any rate.

Why are you summing?  Presumably to get harmonic entropy for x,
which is the entropy of the distribution of probabilities for all
p/q.  Does the q^(-d) term do that, and if so, how?

>>A problem with this is that it mixes multiplicative and
>>implicitly additive distance measures, since |log(p/q)-x| is
>>multiplicative, while q does not depend on the octave and,
>>like the Farey sequence, is implicitly additive.
>
>I think maybe the plan should be to get a continuous function
>the Tenney Height way, by
>
>sum_{p/q > 0} Pc(x, p/q)/(p*q)

Um, not clear how this could possibly work.  Paul empirically
verified that p*q approximates the "width" (and also the entropy?)
for x.  Where I'm totally at a loss for how to define "width".

Anyway, goal number 1 is to do extend things to triads and
up.  Where I think p*q*r is supposed tell you something about the
space around triads on a 2-D plot...  or something.  It's been
a long time...

-Carl


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Message: 7072

Date: Wed, 23 Jul 2003 03:59:22

Subject: Re: Interesting numerical coincidences (Combinatorics etc)

From: Paul Erlich

--- In tuning-math@xxxxxxxxxxx.xxxx "paulhjelmstad" 

> Another cool coincidence. C{19,6} reduces to a count of 735 unique 
> interval vectors. That's 49 X 15. 49 and 15 appear along "Kleismic"
> in the zoom diagram.

what's the coincidence? any two ets will be collinear along some 
line, whether the particular line connecting them is special enough 
to merit inclusion on the chart or not -- and quite a few did. any 
two ets define a 5-limit linear temperament (represented by a line in 
the diagram).


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