Generator-offset property: Difference between revisions

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== Theorems ==
== Theorems ==
<!--=== Theorem 1 ===  
=== Theorem 1 ===  
Let ''S'' be a 3-step-size scale word in L, M, and s, and suppose ''S'' is alt-gen. Then:
Let ''S'' be a 3-step-size scale word in L, M, and s, and suppose ''S'' is ASWFG. Then:
# ''S'' is unconditionally MV3 (i.e. MV3 regardless of tuning).
# ''S'' is unconditionally MV3 (i.e. MV3 regardless of tuning).
# ''S'' is of the form ''ax by bz'' for some permutation (''x'', ''y'', ''z'') of (L, M, s).
# ''S'' is of the form ''ax by bz'' for some permutation (''x'', ''y'', ''z'') of (L, M, s).
# The cardinality (size) of ''S'' is either odd, or 4 (and ''S'' is of the form ''xyxz'').
# The cardinality (size) of ''S'' is either odd, or 4 (and ''S'' is of the form ''xyxz'').
==== Proof ====
==== Proof ====
Assuming alt-gen, we have two chains of generator ''g''<sub>0</sub> (going right). The two cases are:
Assuming ASWFG, we have two chains of generator ''g''<sub>0</sub> (going right). The two cases are:
  CASE 1: EVEN CARDINALITY
  CASE 1: EVEN CARDINALITY
  O-O-...-O (n/2 notes)
  O-O-...-O (n/2 notes)
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(The above holds for any odd ''n'' ≥ 3.)
(The above holds for any odd ''n'' ≥ 3.)


Now we only need to see that alt-gen + odd cardinality => unconditionally MV3. But the argument in case 2 above works for any interval class (unconditional MV3 wasn't used), hence any interval class comes in at most 3 sizes regardless of tuning.-->
Now we only need to see that ASWFG + odd cardinality => unconditionally MV3. But the argument in case 2 above works for any interval class (unconditional MV3 wasn't used), hence any interval class comes in at most 3 sizes regardless of tuning.-->


== Conjectures ==
== Conjectures ==