TM-Reduced Lattice Basis
"T" stands for Tenney [James Tenney, composer and music-theorist], "M" for Minkowski [Hermann Minkowski, mathematician]. A method for reducing the basis of a lattice. First we need to define Tenney height. if p / q is a positive rational number in reduced form, then the Tenney height is TH(p / q) = p · q.
Now suppose {q1, ..., qn} are n multiplicatively linearly independent positive rational numbers. Linear independence can be equated, for instance, with the condition that rank of the matrix whose rows are the monzos for qi is n. Then {q1, ..., qn} is a basis for a lattice
L, consisting of every positive rational number of the form q1e1 ... q1en where the ei are integers and where the log of the Tenney height defines a norm. Let t1 > 1 be the shortest (in terms of Tenney height) rational number in L greater than 1. Define ti > 1 inductively
as the shortest number in L independent of {t1, ... ti-1} and such that {t1, ..., ti} can be extended to be a basis for L. In this way we obtain {t1, ..., tn}, the TM reduced basis of L. See this definition of Minkowski reduction and definitions by Gene Ward Smith.
. . . . . . . . .
5-Limit Base Examples
Here are some of the 5-limit TM-reduced lattice bases and the resulting periodicity blocks, rendered in Tonalsoft™ Tonescape™ software. The purple lines are the two unison-vectors which form the lattice basis, the spheres represent the exponents of the prime-factors 3 and 5, which designate the ratios in the just-intonation version of the tuning, the pink lines connect the ratios together along the 3-axes, and the green lines connect the ratios along the 5-axes, showing the periodicity-block structure. Note that in the rectangular lattices the pink connectors represent only the 3 and 5 axes, while in the triangular lattices there is also a third connector which represents an axis containing both 3 and 5: in these images these are also colored green. Note also that the toroidal lattices cannot show the unison-vectors, because in that geometry the unison-vectors are reduced to a point. (Two higher-dimensional examples are also shown at the bottom of this page.)
12 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
syntonic-comma |
2-4 34 5-1 |
[-4 4, -1> |
81 / 80 |
21.5062896 |
enharmonic-diesis |
27 30 5-3 |
[ 7 0, -3> |
128 / 125 |
41.05885841 |
rectangular
triangular
toroidal
15 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
enharmonic-diesis |
27 30 5-3 |
[ 7 0, -3> |
128 / 125 |
41.05885841 |
maximal-diesis (porcupine-comma) |
21 3-5 53 |
[ 1 -5, 3> |
250 / 243 |
49.16613727 |
rectangular
triangular
toroidal
19 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
syntonic-comma |
2-4 34 5-1 |
[-4 4, -1> |
81 / 80 |
21.5062896 |
magic-comma |
2-10 3-1 55 |
[-10 -1, 5> |
3,125 / 3,072 |
29.61356846 |
rectangular
triangular
toroidal
22 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
diaschisma |
211 3-4 5-2 |
[11 -4, -2> |
2,048 / 2,025 |
19.55256881 |
maximal-diesis (porcupine-comma) |
21 3-5 53 |
[ 1 -5, 3> |
250 / 243 |
49.16613727 |
rectangular
triangular
toroidal
31 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
würschmidt-comma |
217 31 5-8 |
[17 1, -8> |
393,216 / 390,625 |
11.44528995 |
syntonic-comma |
2-4 34 5-1 |
[-4 4, -1> |
81 / 80 |
21.5062896 |
rectangular
triangular
toroidal
34 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
kleisma |
2-6 3-5 56 |
[-6 -5, 6> |
15,625 / 15,552 |
8.107278862 |
diaschisma |
211 3-4 5-2 |
[11 -4, -2> |
2,048 / 2,025 |
19.55256881 |
rectangular
triangular
toroidal
34 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
minimal-diesis |
25 3-9 54 |
[5 -9 4> |
20,000 / 19,683 |
27.65984767085246 |
magic-comma |
2-10 3-1 55 |
[-10 -1, 5> |
3,125 / 3,072 |
29.61356846 |
rectangular
triangular
toroidal
53 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
skhisma |
2-15 38 51 |
[-15, 8, 1> |
32,805 / 32,768 |
1.953720788 |
kleisma |
2-6 3-5 56 |
[-6 -5, 6> |
15,625 / 15,552 |
8.107278862 |
rectangular
triangular
toroidal
55 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
syntonic-comma |
2-4 34 5-1 |
[-4 4, -1> |
81 / 80 |
21.5062896 |
(unnamed?) |
227 35 5-15 |
[ 27, 5, -15> |
32,614,907,904 / 30,517,578,125 |
115.069296354415 |
rectangular
triangular
toroidal
65 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
skhisma |
2-15 38 51 |
[-15, 8, 1> |
32,805 / 32,768 |
1.953720788 |
sensipent-comma |
22 39 5-7 |
[ 2, 9, -7> |
78,732 / 78,125 |
13.39901073 |
rectangular
triangular
toroidal
81 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
majvam |
240 37 5-22 |
[40, 7, -22> |
2,404,631,929,946,112 / 2,384,185,791,015,625 |
14.78330103134586 |
syntonic-comma |
2-4 34 5-1 |
[-4 4, -1> |
81 / 80 |
21.5062896 |
rectangular
triangular
toroidal
For purposes of illustrating the lattice bases, the letter notation is largely irrelevant for cardinalities larger than 81-ed2, so all subsequent lattices will show notation only in the logarithmic ED2 degrees.
118 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
skhisma |
2-15 38 51 |
[-15, 8, 1> |
32,805 / 32,768 |
1.953720788 |
parakleisma |
28 314 5-13 |
[ 8, 14, -13> |
1,224,440,064 / 1,220,703,125 |
5.291731873 |
rectangular
toroidal
171 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
skhisma |
2-15 38 51 |
[-15, 8, 1> |
32,805 / 32,768 |
1.953720788 |
19-tone-comma |
2-14 3-19 519 |
[ -14, -19, 19> |
19,073,486,328,125 / 19,042,491,875,328 |
2.8155469895004357 |
rectangular
toroidal
270 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
vishnuzma (semisuper-comma) |
223 36 5-14 |
[ 23, 6, -14> |
6,115,295,232 / 6,103,515,625 |
3.3380110846370235 |
vulture-comma |
224 3-21 54 |
[24, -21, 4> |
10,485,760,000 / 10,460,353,203 |
4.199837286203549 |
289 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
(unnamed?) |
222 333 5-32 |
[ 22 33, -32> |
23,316,389,970,546,096,340,992 / 23,283,064,365,386,962,890,625 |
2.4761848830704634 |
skhisma |
2-15 38 51 |
[-15, 8, 1> |
32,805 / 32,768 |
1.953720788 |
441 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
ennealimma |
21 3-27 518 |
[ 1, -27, 18> |
7,629,394,531,250 / 7,625,597,484,987 |
0.861826202 |
lunama (hemithirds-comma) |
238 3-2 5-15 |
[38, -2, -15> |
274,877,906,944 / 274,658,203,125 |
1.384290297 |
559 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
lunama (hemithirds-comma) |
238 3-2 5-15 |
[38, -2, -15> |
274,877,906,944 / 274,658,203,125 |
1.384290297 |
minortonic-comma |
2-16 335 5-17 |
[-16, 35, -17> |
50,031,545,098,999,707 / 50,000,000,000,000,000 |
1.091894586 |
612 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
kwazy |
2-53 310 516 |
[-53, 10, 16> |
9,010,162,353,515,625 / 9,007,199,254,740,992 |
0.569430491 |
ennealimma |
21 3-27 518 |
[ 1, -27, 18> |
7,629,394,531,250 / 7,625,597,484,987 |
0.861826202 |
rectangular
toroidal top view
toroidal close up
toroidal side-view
730 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
minortonic-comma |
2-16 335 5-17 |
[-16, 35, -17> |
50,031,545,098,999,707 / 50,000,000,000,000,000 |
1.091894586 |
kwazy |
2-53 310 516 |
[-53, 10, 16> |
9,010,162,353,515,625 / 9,007,199,254,740,992 |
0.569430491 |
When the cardinality of the EDO gets this high, it is difficult to see a difference in the geometry of their toruses, so graphics for the following are omitted. In addition, ratios are omitted from the list of unison-vectors, because of the size of the numbers in their numerators and denominators, with only the factors shown.
1,171 ET/EDO and Above
Example of a 3-dimensional TM-basis
31 ET/EDO in 3,5,7-space
name |
factors |
monzo |
ratio |
~cents |
septimal-kleisma |
2-5 32 52 7-1 |
[ -5, 2, 2, -1> |
225 / 224 |
7.711522991319706 |
orwellisma |
26 33 5-1 7-3 |
[ 6, 3, -1, -3> |
1,728 / 1,715 |
13.07356932395248 |
syntonic-comma |
2-4 34 5-1 70 |
[-4, 4, -1, 0> |
81 / 80 |
21.50628959671478 |
Example of a 4-dimensional TM-basis
270-edo (tredeks) is used as an illustration here because of its excellence as a simpler integer replacement for cents in the 11-limit.
270 ET/EDO
name |
factors |
monzo |
ratio |
~cents |
kalisma |
2-3 34 5-2 7-2 112 |
[-3 4 -2 -2 2> |
9,801 / 9,800 |
0.1766475231436913 |
lehmerisma |
2-4 3-3 52 7-1 112 |
[-4 -3 2 -1 2> |
3,025 / 3,024 |
0.5724033938959937 |
breedsma |
2-5 3-1 5-2 74 110 |
[ -5 -1 -2 4 0> |
2,401 / 2,400 |
0.7211972814427758 |
vishdel |
29 3-2 5-4 70 111 |
[9 -2 -4 0 1> |
5,632 / 5,625 |
2.1530851746424933 |
. . . . . . . . .