@chesscom@LoudovicB You evaluate an earlier branch of the decision tree that rules out that entire subtree. You do not literally need to brute force every single position in chess, in principle.
@AlexKontorovich One thing I have never got about Lean: is intuitionistic logic required when proving this kind of thing? Because given that IsOdd(n) is defined as !IsEven(n), all we are saying is, "IsEven(n) | !IsEven(n)" which follows immediately from excluded middle. Is that legal, though?
@JDHamkins Note that the converse is also true: if you can make it anywhere, you can trivially thus make it in New York. Thus, via another contrapositive, if you can't make it in New York, you can't make it anywhere. You can only make it anywhere iff you can make it in New York.
@JDHamkins Is the idea that you have a countable model and add the same countable set of reals to it in different orders? In one model you add it ordered as what the model thinks is omega_1, in the second you add it ordered as omega_2.
@AnalysisFact Roses are red,
Violets are blue,
I've noticed that most poems on the internet abandon all sense of meter and cram a bunch of syllables in the middle and then throw in a rhyme at the end,
Have you noticed this too?