On Fri, Apr 9, 2021 at 6:09 PM Stéfane Fermigier
I think the best alias for "empty set" would be the Unicode character "Empty set" or U+2205, i.e. "∅".
Alas, it's not a valid identifier in Python:
∅ = set() File "<stdin>", line 1 ∅ = set() ^ SyntaxError: invalid character '∅' (U+2205)
It works with the similarly looking "ϕ" or 'GREEK PHI SYMBOL' (U+03D5)
ϕ = set() ϕ.union({1,2}) {1, 2}
But it's less than ideal.
I think it's an error from the Unicode standard to list the empty set as a "Mathematical Operator" (https://en.wikipedia.org/wiki/Mathematical_operators_and_symbols_in_Unicode#...) and not as a "Letterlike Symbol" like ℝ or ℕ (https://en.wikipedia.org/wiki/Mathematical_operators_and_symbols_in_Unicode#...).
Ex:
ℕ = [0, ...] # Whatever that means... ℕ [0, Ellipsis]
So yes, the language would need to be changed to allow the proper empty set unicode symbol to be used.
Not to mention everyone's keyboards. Python != APL. Err, I mean, Python ≠ APL. ChrisA