Graph-theoretic properties of scales: Difference between revisions
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However arrived at, the scale in [[197edo|197et]] is 0, 19, 63, 82, 115, 134, 178, 197. It has two graphs of interest, since the graphs of 7-limit relations and of 9-limit relations are not isomorphic, but the automorphism groups (of order 16) of these graphs are. The 7-limit consonance set is {38, 44, 52, 63, 82, 96, 101, 115, 134, 145, 153, 159, 197} and the 9-limit set is {30, 33, 38, 44, 52, 63, 71, 82, 96, 101, 115, 126, 134, 145, 153, 159, 164, 167, 197}. The difference is {30, 33, 71, 126, 164, 167}. In Gypsy, the 9-limit intervals occur between 5/4 and 8/5, tempered to 9/7, and between 4/3 and 3/2. | However arrived at, the scale in [[197edo|197et]] is 0, 19, 63, 82, 115, 134, 178, 197. It has two graphs of interest, since the graphs of 7-limit relations and of 9-limit relations are not isomorphic, but the automorphism groups (of order 16) of these graphs are. The 7-limit consonance set is {38, 44, 52, 63, 82, 96, 101, 115, 134, 145, 153, 159, 197} and the 9-limit set is {30, 33, 38, 44, 52, 63, 71, 82, 96, 101, 115, 126, 134, 145, 153, 159, 164, 167, 197}. The difference is {30, 33, 71, 126, 164, 167}. In Gypsy, the 9-limit intervals occur between 5/4 and 8/5, tempered to 9/7, and between 4/3 and 3/2. | ||
If we call the automorphism group of the 7-limit graph G7 and that of the 9-limit group G9, then G7 is guaranteed to send 7-limit intervals to 7-limit intervals, but will not necessarily send 9-limit intervals to a consonance. G9 must send 9-limit intervals to 9-limit intervals, but may send a 7-limit interval to the 9-limit. The intersection G7∩G9 is a group of order eight which sends 7-limit intervals to 7-limit intervals, and strictly 9-limit intervals, those of [[Kees height]] 9, to strictly 9-limit intervals; it can't send such intervals to the 7-limit without the inverse sending a 7-limit interval to the 9-limit. G7∩G9 = {0123456, 0132546, 0145236, 0154326, 0623451, 0632541, 0645231, 0654321}, G7\G9 = {0125436, 0134526, 0143256, 0152346, 0625431, 0634521, 0643251, 0652341}, and G9\G7 = {0123546, 0132456, 0145326, 0154236, 0623541, 0632451, 0645321, 0654231}. G7 and G9 are intransitive; one orbit consists of the fixed center interval 0, and an involution exchanges the extreme intervals 0 and 6. The other four points are permuted by the group of the square in two different representations for G7 and G9. | |||
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However arrived at, the scale in <a class="wiki_link" href="/197edo">197et</a> is 0, 19, 63, 82, 115, 134, 178, 197. It has two graphs of interest, since the graphs of 7-limit relations and of 9-limit relations are not isomorphic, but the automorphism groups (of order 16) of these graphs are. The 7-limit consonance set is {38, 44, 52, 63, 82, 96, 101, 115, 134, 145, 153, 159, 197} and the 9-limit set is {30, 33, 38, 44, 52, 63, 71, 82, 96, 101, 115, 126, 134, 145, 153, 159, 164, 167, 197}. The difference is {30, 33, 71, 126, 164, 167}. In Gypsy, the 9-limit intervals occur between 5/4 and 8/5, tempered to 9/7, and between 4/3 and 3/2.<br /> | However arrived at, the scale in <a class="wiki_link" href="/197edo">197et</a> is 0, 19, 63, 82, 115, 134, 178, 197. It has two graphs of interest, since the graphs of 7-limit relations and of 9-limit relations are not isomorphic, but the automorphism groups (of order 16) of these graphs are. The 7-limit consonance set is {38, 44, 52, 63, 82, 96, 101, 115, 134, 145, 153, 159, 197} and the 9-limit set is {30, 33, 38, 44, 52, 63, 71, 82, 96, 101, 115, 126, 134, 145, 153, 159, 164, 167, 197}. The difference is {30, 33, 71, 126, 164, 167}. In Gypsy, the 9-limit intervals occur between 5/4 and 8/5, tempered to 9/7, and between 4/3 and 3/2.<br /> | ||
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If we call the automorphism group of the 7-limit graph G7 and that of the 9-limit group G9, then G7 is guaranteed to send 7-limit intervals to 7-limit intervals, but will not necessarily send 9-limit intervals to a consonance. G9 must send 9-limit intervals to 9-limit intervals, but may send a 7-limit interval to the 9-limit. The intersection G7∩G9 is a group of order eight which sends 7-limit intervals to 7-limit intervals, and strictly 9-limit intervals, those of <a class="wiki_link" href="/Kees%20height">Kees height</a> 9, to strictly 9-limit intervals; it can't send such intervals to the 7-limit without the inverse sending a 7-limit interval to the 9-limit. G7∩G9 = {0123456, 0132546, 0145236, 0154326, 0623451, 0632541, 0645231, 0654321}, G7\G9 = {0125436, 0134526, 0143256, 0152346, 0625431, 0634521, 0643251, 0652341}, and G9\G7 = {0123546, 0132456, 0145326, 0154236, 0623541, 0632451, 0645321, 0654231}. G7 and G9 are intransitive; one orbit consists of the fixed center interval 0, and an involution exchanges the extreme intervals 0 and 6. The other four points are permuted by the group of the square in two different representations for G7 and G9.<br /> | |||
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