Equivalence continuum: Difference between revisions

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List of equivalence continua: + justifications for most of these entries
 
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An '''equivalence continuum''' comprises all the [[regular temperament|temperaments]] where a number of a certain interval is equated with another interval. Specifically, if the first interval, which we may call the stacked interval, is ''q''<sub>1</sub>, and the second interval, which we may call the targeted interval, is ''q''<sub>2</sub>, both in [[ratio]]s, an equivalence continuum is formed by all the temperaments that satisfy {{nowrap| {{subsup|''q''|1|''n''}} ~ ''q''<sub>2</sub> }}, where ''n'' is an arbitrary rational number. An equivalence continuum creates a space of temperaments on a specified [[JI subgroup]] that are [[support]]ed by a specified temperament of a lower rank (such as an [[equal temperament]]) on the same subgroup.  
An '''equivalence continuum''' comprises all the [[regular temperament|temperaments]] where a number of a certain interval is equated with another interval. Specifically, if the first interval, which we may call the stacked interval, is ''q''<sub>1</sub>, and the second interval, which we may call the targeted interval, is ''q''<sub>2</sub>, both in [[ratio]]s, an equivalence continuum is formed by all the temperaments that satisfy {{nowrap| {{subsup|''q''|1|''n''}} ~ ''q''<sub>2</sub> }}, where ''n'' is an arbitrary rational number. An equivalence continuum creates a space of temperaments on a specified [[JI subgroup]] that are [[support]]ed by a specified temperament of a lower rank (such as an [[equal temperament]]) on the same subgroup.  


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== Geometric interpretation ==
== Geometric interpretation ==
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Mathematically, the rank-''k'' '''equivalence continuum''' C(''k'',&nbsp;''T'') associated with a rank-''r'' temperament ''T'' on a rank-''n'' subgroup ''S'' is the space of [[Mathematical theory of saturation|saturated]] ({{nowrap|''n − k''}})-dimensional sublattices of the [[kernel]] (set of all intervals tempered out) of ''T'', the rank-({{nowrap|''n − r''}}) lattice of commas tempered out by ''T''. This is a set of rational points on the Grassmannian {{nowrap|'''G''' {{=}} '''Gr'''(''n − k'', ''n − r'')}} of ({{nowrap|''n − k''}})-dimensional vector subspaces of '''R'''<sup>{{nowrap|''n'' − ''r''}}</sup>, identifying '''R'''<sup>{{nowrap|''n'' − ''r''}}</sup> with the '''R'''-vector space {{nowrap|ker(''T'') &otimes; '''R'''}}.
Mathematically, the rank-''k'' '''equivalence continuum''' C(''k'',&nbsp;''T'') associated with a rank-''r'' temperament ''T'' on a rank-''n'' subgroup ''S'' is the space of [[Mathematical theory of saturation|saturated]] ({{nowrap|''n − k''}})-dimensional sublattices of the [[kernel]] (set of all intervals tempered out) of ''T'', the rank-({{nowrap|''n − r''}}) lattice of commas tempered out by ''T''. This is a set of rational points on the Grassmannian {{nowrap|'''G''' {{=}} '''Gr'''(''n − k'', ''n − r'')}} of ({{nowrap|''n − k''}})-dimensional vector subspaces of '''R'''<sup>{{nowrap|''n'' − ''r''}}</sup>, identifying '''R'''<sup>{{nowrap|''n'' − ''r''}}</sup> with the '''R'''-vector space {{nowrap|ker(''T'') &otimes; '''R'''}}.


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* [[5-limit]] rank-2 continua include:  
* [[5-limit]] rank-2 continua include:  
** the [[father–3 equivalence continuum]] ([[3edo]])
** the [[father–3 equivalence continuum]] ([[3edo]], a 3- and 5-limit record edo)
** the [[syntonic–diatonic equivalence continuum]] ([[5edo]])
** the [[syntonic–diatonic equivalence continuum]] ([[5edo]], a 3- and 5-limit record edo)
** the [[syntonic–chromatic equivalence continuum]] ([[7edo]])
** the [[syntonic–chromatic equivalence continuum]] ([[7edo]], a 3- and 5-limit record edo)
** the [[schismic–Pythagorean equivalence continuum]] ([[12edo]])
** the [[schismic–Pythagorean equivalence continuum]] ([[12edo]], a 3- and 5-limit record edo)
** the [[syntonic–kleismic equivalence continuum]] ([[19edo]])
** the [[syntonic–kleismic equivalence continuum]] ([[19edo]], a 5-limit record edo)
** the [[superpyth–22 equivalence continuum]] ([[22edo]])
** the [[superpyth–22 equivalence continuum]] ([[22edo]])
** the [[syntonic–31 equivalence continuum]] ([[31edo]])
** the [[syntonic–31 equivalence continuum]] ([[31edo]], a 5-limit record edo)
** the [[diaschismic–gothmic equivalence continuum]] ([[34edo]])
** the [[diaschismic–gothmic equivalence continuum]] ([[34edo]], a 5-limit record edo)
** the [[schismic–countercommatic equivalence continuum]] ([[41edo]])
** the [[schismic–countercommatic equivalence continuum]] ([[41edo]], a 3-limit record edo)
** the [[schismic–Mercator equivalence continuum]] ([[53edo]])
** the [[schismic–Mercator equivalence continuum]] ([[53edo]], a 3- and 5-limit record edo)
** the [[ennealimmal–enneadecal equivalence continuum]] ([[171edo]])
** the [[ennealimmal–enneadecal equivalence continuum]] ([[171edo]], a 5-limit record edo)
** the [[tarot equivalence continuum]] ([[1848edo]])
** the [[tarot equivalence continuum]] ([[1848edo]])


* [[2.3.7&nbsp;subgroup]] rank-2 continua include:
* [[2.3.7 subgroup|2.3.7-subgroup]] rank-2 continua include:
** the [[Archytas–chromatic equivalence continuum]] ([[7edo]])
** the [[Archytas–diatonic equivalence continuum]] ([[5edo]], a 3-limit and 2.3.7-subgroup record edo)
** the [[Archytas–diatonic equivalence continuum]] ([[5edo]])
** the [[Archytas–chromatic equivalence continuum]] ([[7edo]], a 3-limit record edo)


* [[2.5.7&nbsp;subgroup]] rank-2 continua include:
* [[2.5.7 subgroup|2.5.7-subgroup]] rank-2 continua include:
** the [[jubilismic–augmented equivalence continuum]] ([[6edo]])
** the [[jubilismic–augmented equivalence continuum]] ([[6edo]], a 2.5.7-subgroup record edo)
** the [[augmented–cloudy equivalence continuum]] ([[15edo]])
** the [[augmented–cloudy equivalence continuum]] ([[15edo]], a 2.5.7-subgroup record edo)
** the [[rainy–didacus equivalence continuum]] ([[31edo]])
** the [[rainy–didacus equivalence continuum]] ([[31edo]], a 2.5.7-subgroup record edo)


* [[3.5.7&nbsp;subgroup]] rank-2 continua include:
* [[3.5.7 subgroup|3.5.7-subgroup]] rank-2 continua include:
** the [[sensamagic–gariboh equivalence continuum]] ([[13edt]])
** the [[sensamagic–gariboh equivalence continuum]] ([[13edt]], a 3.5.7-subgroup record edo)


* [[7-limit]] rank-3 continua include:
* [[7-limit]] rank-3 continua include:
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** the [[breedsmic–syntonic equivalence continuum]] ([[squares]])
** the [[breedsmic–syntonic equivalence continuum]] ([[squares]])


* [[2.3.5.11&nbsp;subgroup]] rank-3 continua include:
* [[2.3.5.11 subgroup|2.3.5.11-subgroup]] rank-3 continua include:
** the [[syntonic–rastmic equivalence continuum]] ([[mohaha]])
** the [[syntonic–rastmic equivalence continuum]] ([[mohaha]])