Are Patents Property? Depends on what you mean…
2 hours ago
Monday, October 05, 2009
Reverse Polish sausage
I'm not enough of a logician to laugh at the latest xkcd, though I did manage to figure out the joke without looking anything up.
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4 comments:
well, that makes one of us. Any chance you can explain it?
There's a kind of mathematical notation called polish notation where instead of writing 3+2 you write + 3 2. I guess in reverse polish notation you write 3 2 +. I don't know how you do parentheses in these notations, but the order is going to be all weird in a way that parallels the situation with the buns and sausage.
I once asked some Polish people whether their language put the connectives before the terms being connected, like in Polish Notation. They said no.
Actually, it's called Polish because it was invented by the Polish logician Jan Łukasiewicz back in 1920. See http://en.wikipedia.org/wiki/Prefix_notation
>I don't know how you do
> parentheses in these notations
You don't need to. That is the main point of these notations.
(3+4)*2 == * + 2 3 4 == 2 4 3 + *
In addition to removing the need for parentheses, RPN also allows for calculations to be done in a simple stack. http://en.wikipedia.org/wiki/Reverse_Polish_notation#Example
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