Thank you for the detailed explanation, Asmus.
Is there a standard denoting which characters are part of each "mathematical variable alphabet"? There is a table on Wikipedia < https://en.wikipedia.org/wiki/Mathematical_Alphanumeric_Symbols#Latin_letters> but the placement of characters into the gaps is unsourced. Perhaps I'm overthinking this, but I don't think it's necessarily obvious that the character BLACK-LETTER CAPITAL C should be used as the nonexistent character *MATHEMATICAL FRAKTUR CAPITAL C. Is there a document clarifying this?
