This might be a silly question, but it's been bugging me for a while. In analysis and calculus, I keep seeing two slightly different-looking symbols used for epsilon. One that looks like a rounded E (ɛ) (aka backwards 3 symbol) and the classic greek epsilon (ε). Most textbooks and professors seem to use them interchangeably, but they're technically different unicode characters.

Does the distinction ever matter mathematically? Or is it just a font thing? I've noticed Mathematica uses \[Epsilon]. is that the greek one or the open-e variant? Curious if anyone has run into actual confusion from this in contexts of formal proofs or when copy pasting.