> I am certain their Navier-Stokes proof is incorrect.
Unless you want the negate the certainty part, but then the nudge to gambling is less coherent.
you might want to think a little bit harder on this
(X and Y) => Z
<=>
~Z => (~X or ~Y)
The person you are arguing with made no such claim of certainty either one way or the other, so they have no reason to bet anything.
this is a very simple exercise in propositional logic (simple enough that i don't need to write a lean proof):
"if you are certain then you should bet"
<=>
"if you're not betting then you're not certain"
so i don't have a "bar" and i'm not saying you shouldn't comment, i'm simply calling you a liar.
Turnabout is fair play.
edit: in other words, if there is anything that he should bet on, it's "the other guy wasn't really certain that the proof is wrong, he is just bloviating". That's a different bet than "the proof is correct".