Erac
From Xenharmonic Reference
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Eracs, short for error accidentals, are symbols that denote error cancelation in a subgroup. This is especially important in the context of Straddle primes.
| < | Flat by a set arbitrary amount. |
| <> | Critically flat/sharp. |
| > | Sharp by a set arbitrary amount. |
Eracs can be placed before or after a number, although it is preferred in ratios for the denominator to have the erac adjacent to the slash. Eracs on the denominator have an inverse effect on the size of a tempered ratio.
For example, 37edo could be called 2.<<3.>3.5.7.11.13, such that adding the flat 3 and two sharp 3s results in a good 27.
See also: erac temperament optimization [[1]]
