Temperament addition: Difference between revisions

Cmloegcmluin (talk | contribs)
m Introductory examples: I feel like I'm going to be fixing these equal signs problems forever hehe
Cmloegcmluin (talk | contribs)
Introductory examples: acknowledge potentially surprising effects of canonical form earlier
Line 125: Line 125:




We could write this in ratio form — replacing addition with multiplication and subtraction with division — as 80/81 × 250/243=20000/19683 and 80/81 ÷ 250/243=25/24, respectively. The similarity in these temperaments can be seen in how all of them are supported by 7-ET.
We could write this in ratio form — replacing addition with multiplication and subtraction with division — as 80/81 × 250/243=20000/19683 and 80/81 ÷ 250/243=25/24, respectively. The similarity in these temperaments can be seen in how all of them are supported by 7-ET. (Note that these examples are all given in canonical form, which is why we're seeing the meantone comma as 80/81 instead of the more common 81/80; for the reason why, see [[Temperament arithmetic#Negation]].)


Temperament arithmetic is simplest for temperaments which can be represented by single vectors such as demonstrated in these examples. In other words, it is simplest for temperaments that are either rank-1 ([[equal temperament]]s, or ETs for short) or nullity-1 (having only a single comma). Because [[grade]] <math>g</math> is the generic term for rank <math>r</math> and nullity <math>n</math>, we could define the minimum grade <math>g_{\text{min}}</math> of a temperament as the minimum of its rank and nullity <math>\min(r,n)</math>, and so for convenience in this article we will refer to <math>r=1</math> (read "rank-1") or <math>n=1</math> (read "nullity-1") temperaments as <math>g_{\text{min}}=1</math> (read "min-grade-1") temperaments. We'll also use <math>g_{\text{max}}</math> (read "max-grade"), which naturally is equal to <math>\max(r,n)</math>.
Temperament arithmetic is simplest for temperaments which can be represented by single vectors such as demonstrated in these examples. In other words, it is simplest for temperaments that are either rank-1 ([[equal temperament]]s, or ETs for short) or nullity-1 (having only a single comma). Because [[grade]] <math>g</math> is the generic term for rank <math>r</math> and nullity <math>n</math>, we could define the minimum grade <math>g_{\text{min}}</math> of a temperament as the minimum of its rank and nullity <math>\min(r,n)</math>, and so for convenience in this article we will refer to <math>r=1</math> (read "rank-1") or <math>n=1</math> (read "nullity-1") temperaments as <math>g_{\text{min}}=1</math> (read "min-grade-1") temperaments. We'll also use <math>g_{\text{max}}</math> (read "max-grade"), which naturally is equal to <math>\max(r,n)</math>.