Recursive structure of MOS scales: Difference between revisions

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=== Reduced words from chunking are binary and preserve the gcd of the step signature ===
=== Reduced words from chunking are binary and preserve the gcd of the step signature ===
It now remains to show that reduction and expansion preserve the MOS property.
We must show that reduction and expansion preserve the MOS property.


Suppose w(L, s) had three chunks L...s with r, r+1 and r+2 'L's. Then we have a length r+2 subword that's only 'L's, one that has one s at the end and one that has two 's's on either side, which means that the original scale was not MOS. Therefore the reduced word has two step sizes.
Suppose w(L, s) had three chunks L...s with r, r+1 and r+2 'L's. Then we have a length r+2 subword that's only 'L's, one that has one s at the end and one that has two 's's on either side, which means that the original scale was not MOS. Therefore the reduced word has two step sizes.