Aristophanes of Byzantium needed to complete each fragment of text when reading aloud (not to comply with rules of grammar, which were not applied to punctuation marks until thousands of years later). For a short passage (a "komma"), a "stigmḕ mésē" dot was placed mid-level (·). This is the origin of the modern comma punctuation mark, and its name. For a longer passage (a "kolon"), a "hypostigmḗ" dot was placed level with the bottom of the text (.), similar to a modern colon or semicolon, and for very long pauses ("periodos"), a "stigmḕ teleía" point near the top of the line of text
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