Unicode usage in comments

How far should we go with unicode symbols to make comments more readable? We already use `∈` and `±`. Other possible substitutions: - all greek letters and special TeX sequences (e.g. `\ell` -> `ℓ`) (see https://milde.users.sourceforge.net/LUCR/Math/unimathsymbols.html) - `\eps` should be `\varepsilon` (`𝜀`) - other stuff: N₀ √ ≡ - `floor`/`ceil` with `⌊⌋`/`⌈⌉` - `\hat` with the corresponding Unicode modifier? I am not sure how much of Unicode can be expected to be supported by various editors/Github.