Height: Difference between revisions
→Examples of height functions: Moved from the general complexity article |
equivalence section: no need to talk about p-adic valuations here |
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Exponentiation and logarithm are such functions commonly used for converting a height between arithmetic and logarithmic scales. | Exponentiation and logarithm are such functions commonly used for converting a height between arithmetic and logarithmic scales. | ||
A '''semi-height''' is a function which does not obey criterion #3 above, so that there is a rational number ''q'' ≠ 1 such that H(''q'') = H(1), resulting in an equivalence relation on its elements, under which #1 is modified to a finite number of equivalence classes. An example would be [[octave equivalence]], where two ratios ''q''<sub>1</sub> and ''q''<sub>2</sub> are considered equivalent if | A '''semi-height''' is a function which does not obey criterion #3 above, so that there is a rational number ''q'' ≠ 1 such that H(''q'') = H(1), resulting in an equivalence relation on its elements, under which #1 is modified to a finite number of equivalence classes. An example would be [[octave equivalence]], where two ratios ''q''<sub>1</sub> and ''q''<sub>2</sub> are considered equivalent if they differ only by factors of 2. | ||
We can also consider other equivalences. For example, we can assume tritave equivalence by ignoring factors of 3. | |||
== Height versus norm == | == Height versus norm == |