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Emmanuel Amiot Modèles algébriques et algorithmes pour la ...

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6 title on some pages<br />

Definition 2.1 The pc-s<strong>et</strong> A ⊂ Zc, with cardinality d, is a ME s<strong>et</strong>, if the number |FA(d)| is maximal<br />

among the values |FX(d)| for all pc-s<strong>et</strong>s X with cardinality d:<br />

∀X ⊂ Zc, Card X = d ⇒ |FA(d)| ≥ |FX(d)|<br />

As the number of pc-s<strong>et</strong>s is finite, a solution must exist. Remember that |FA(d)| = F(ICA)(d) (see<br />

section 1). Therefore, maximal evenness is also manifest in the DFT of the interval vector as a maximality<br />

condition for |F(ICA)(d)|.<br />

From the invariance of the ‘Fourier profile’ |FA| under musical operations (see theorem 1.5 and lemma<br />

1.2 about complementation) we obtain easily<br />

Proposition 2.2 Transposition, inversion and complementation of a ME s<strong>et</strong> still yield a ME s<strong>et</strong>.<br />

2.3 Notations and Maps<br />

Throughout the remainder of this section l<strong>et</strong> m = gcd(d, c) denote the greatest common divisor of d and<br />

c and l<strong>et</strong> d ′ = d<br />

m and c′ = c<br />

denote the associated quotients.<br />

m<br />

L<strong>et</strong> ϕd : Zc → m Zc and ϕd ′ : Zc ′ → Zc ′ denote the linear multiplication maps ϕd(l) = d · l and<br />

ϕd ′(k) = d′ · k, respectively. Further l<strong>et</strong> πc ′ : Zc → Zc ′ denote the reduction of the finer residue c<strong>la</strong>sses<br />

mod c to the coarser residue c<strong>la</strong>sses mod c ′ , i.e. πc ′(l) = l mod c′ . Finally, l<strong>et</strong> im : m Zc → Zc ′ denote the<br />

isomorphism, identifying the submodule m Zc of Zc with Zc ′: im(mk) := k mod c ′ .<br />

Note that the multiplication by d is a concatenation of the multiplications by m and by d ′ title on some pages<br />

. Thus, if we<br />

concatenate the maps ϕd and im into a map πd := im ◦ ϕd, we see that the map im ‘undoes’ the previous<br />

multiplication by m. Therefore im ◦ ϕd = ϕd ′ ◦ πc ′, which means that the diagram below commutes.<br />

of ‘mathemusical’ knowledge is the continued contribution of Jack Douth<strong>et</strong>t<br />

gh and other partners). He is still a beacon in the field of ME s<strong>et</strong>s.<br />

eviewers have been instrumental in bringing this paper up to the quality level<br />

table task for a lone writer. I would like to thank especially Dmitri Tymocsko, R<br />

oll in that respect.<br />

s<br />

A d A mod c<br />

ϕd<br />

Zc<br />

πc<br />

✲ mZc<br />

ϕd ✲<br />

′<br />

❅<br />

❅ πd<br />

❅<br />

❄ ❅❘ ❄<br />

′ ιm<br />

Zc ′<br />

., 2006, Une preuve élégante du théorème de Babbitt par transformée de Fourier discrète, Quadrature,<br />

., The Different Generators of A Scale, 2008, Figure 1. Journal Notations and ofmorphisms Music Theory, to be published.<br />

M., 1955, Some Aspects of Twelve-Tone Composition, Score, 12 , 53-61.<br />

Douth<strong>et</strong>t, J.., 1994, Vector products and intervallic weighting, Journal of Music Theory , 38, 2142.<br />

V., Vicinanza D., 2004, Myhill property, CV, well-formedness, winding numbers and all that, Logique<br />

lles en musique., Keynote adress to MaMuX seminar 2004 - IRCAM - Paris.<br />

., C<strong>la</strong>mpitt, D., 1989, Aspects of Well Formed Scales, Music Theory Spectrum, 11(2),187-206.<br />

., Douth<strong>et</strong>t, J., 1991, Maximally even s<strong>et</strong>s, Journal of Music Theory, 35:93-173.<br />

., Myerson, G., 1985, Vari<strong>et</strong>y and Multiplicity in Diatonic Systems, Journal of Music Theory,29:249-7<br />

., Myerson, G., 1986, Musical Scales and the Generalized Circle of Fifths, AMM, 93:9, 695-701.<br />

, J., Krantz, R., 2007, Maximally even s<strong>et</strong>s and configurations: common threads in mathematics, physics,<br />

Zc ′<br />

B' B A'

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