Tempered monzos and vals: Difference between revisions
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A regular temperament T is an equivalence class of Z-module homomorphisms '''T''': J → K, where J is a Z-module of JI intervals, K is a Z-module of tempered intervals, and two homomorphisms are said to represent the same [[ | A regular temperament T is an equivalence class of Z-module homomorphisms '''T''': J → K, where J is a Z-module of JI intervals, K is a Z-module of tempered intervals, and two homomorphisms are said to represent the same [[temperament]] if they differ only by unimodular transformation. An element of K is called a '''tmonzo''', and an element of the dual module K* is called a '''tval'''. | ||
Tmonzos are rather straightforward, and tvals act on tmonzos in the same way that vals act on monzos: they're linear functionals which map from tmonzos to a scalar representing a certain number of steps. Note that there is no restriction on which bases tmonzos can be written in, but one option is to use the basis corresponding to the [[ | Tmonzos are rather straightforward, and tvals act on tmonzos in the same way that vals act on monzos: they're linear functionals which map from tmonzos to a scalar representing a certain number of steps. Note that there is no restriction on which bases tmonzos can be written in, but one option is to use the basis corresponding to the [[Temperament Mapping Matrices (M-maps)|mapping matrix]] for the temperament which is in [[Normal lists #Normal val list|normal val list]] form. | ||
=Example= | == Example == | ||
As an example, consider the mapping matrix | As an example, consider the mapping matrix | ||
[ | [{{val| 1 1 0 }}] | ||
[ | [{{val| 0 1 4 }}] | ||
This matrix represents meantone temperament. If we right-multiply this matrix by the monzo |1 0 0 | This matrix represents meantone temperament. If we right-multiply this matrix by the monzo {{monzo| 1 0 0 }}, representing 2/1, we get the tmonzo {{monzo| 1 0 }}. If we right-multiply it instead by {{monzo| -1 1 0 }}, we get the tmonzo {{monzo| 0 1 }}. That 2/1 and 3/2 map to {{monzo| 1 0 }} and {{monzo| 0 1 }} respectively tell us that the tempered versions of these intervals can serve as a basis for meantone. If we now right-multiply the matrix by the monzo {{monzo| -2 0 1 }}, representing 5/4, we get the tmonzo {{monzo| -2 4 }}, telling us that the tempered 5/4 maps to four tempered 3/2's minus two tempered 2/1's. | ||
[[Category:Theory]] | |||
[[Category:Val]] | |||
[[Category:Monzo]] | |||