PEP-308 a "simplicity-first" alternative
Erik Max Francis
max at alcyone.com
Wed Feb 12 18:12:27 EST 2003
Michael Hudson wrote:
> In which context? In my world, => is implication. It's even
> $\implies$ in LaTeX, I think. -> is often used to denote a map.
In a logical context. _VNR_ for instance uses the single horizontal
line -> arrow for logical implication (section 15.1).
> > In mathematics when the double line version is used, it's often used
> > to mean something else, like "is equivalent to" or "evaluates to."
>
> Equivalent to is often <=>. Using => to mean equivalence would be
> daft notation, even by mathematical standards.
Or <-> (again, _VNR_ section 15.1). Equvalence to as in equivalence
classes is usually written as three horizontal bars, as we all know.
> I have seen => used to mean "evaluates to", but generally in a
> computer context.
Yes, though I've sene it used in mathematics as well. When I wrote "is
equivalent to," I really meant "evaluates to" or "could be replaced
with," rather than the logical meaning of equivalence (if and only if),
or the meaning with respect to equivalence classes.
--
Erik Max Francis / max at alcyone.com / http://www.alcyone.com/max/
__ San Jose, CA, USA / 37 20 N 121 53 W / &tSftDotIotE
/ \ You cannot step into the same river once.
\__/ Cratylus
Python chess module / http://www.alcyone.com/pyos/chess/
A chess game adjudicator in Python.
More information about the Python-list
mailing list