Comma the purpose of the comma. There are also a number of comma-like diacritics with "COMMA" in their Unicode names. These do not serve a punctuation function. A comma-like low quotation mark is also available (shown below; raised single quotation marks are not shown). Various other Unicode characters combine commas or comma-like figures with other characters, and are not shown here. In the 3rd century BC, Aristophanes of Byzantium invented a system of single dots ("distinctiones") that separated verses (colometry) and indicated the amount of breath needed to complete each fragment of the text when reading aloud. The different lengths were
Comma category by Lawvere, which involved the comma punctuation mark. Although standard notation has changed, since the use of a comma as an operator is potentially confusing, and even Lawvere dislikes the uninformative term "comma category" (Lawvere, 1963 p. 13), the name persists. The most general comma category construction involves two functors with the same codomain. Often one of these will have domain 1 (the one-object one-morphism category). Some accounts of category theory consider only these special cases, but the term comma category is actually much more general. Suppose that formula_1, formula_2, and formula_3 are categories, and formula_4 and formula_5 (for source