Generator gronut/Mathematics: Difference between revisions

From Xenharmonic Reference
Line 14: Line 14:


== Straddle generator structure ==
== Straddle generator structure ==
The gronut graph...
For each vertex (note) of n-edo, draw an edge corresponding to 1\n and two edges for the two generators straddling g\m. The resulting graph is called the '''gronut graph'''.

Revision as of 13:09, 20 October 2026

This is a technical or mathematical page. While the subject may be of some relevance to music, the page treats the subject in technical language.

(Under construction)

Definition

Let m>1 and n>m,gcd⁡(n,m)=1 be integer edos and fix a generator g,2≤g≤m−2 with gcd⁡(g,m)=1. Let h be the modular inverse of g modulo m.

Consider the "cylinder" C=ℤ/m×[0,1) with coordinates (x,y) = (along "longitude", along "meridian"). Follow the following procedure:

  1. Glue copies of the real interval ("line segment") [0,1) end to end, making a (continuous) circle of circumference m. For every copy of [0,1) the next copy is the one that is h steps away along the longitude.
  2. Take n equally spaced points on said circle. For sake of canonicality one of the n points is taken to be a "glue point".
  3. Unglue the line segments and put them back at their original positions.

The resulting sequence of embeddings ℤ/n→S1→C is called the (n,g∖m)-gronut.

Straddle generator structure

For each vertex (note) of n-edo, draw an edge corresponding to 1\n and two edges for the two generators straddling g\m. The resulting graph is called the gronut graph.