[PRL] point-free set notation

[Aaron Turon]

It sounds like you want the relational image.  If R is a binary
relation and X is a set, then RX = {a : a R b, b in X} and XR = {b : a
R b, a in X}.

So for your example you could write (>){n}, often abbreviated by >n
when the types are clear.

On Sat, Jan 9, 2010 at 3:43 PM, David Herman <dherman at ccs.neu.edu> wrote:
> In Haskell, you can curry a binary operator to define a function
> without naming the missing argument:
>
>     (+n) === \m -> (m+n)
>
> Is there an analogous notation in math for constructing a set based on
> a binary relation with an omitted element? For example, I'd like to be
> able to define the set of integers > n like:
>
>     { -- > n } === { m | m > n }
>
> or something like that. (I'm aware that generally this is a type-
> ambiguous notation, but for my purposes the meta-variables involved
> are enough to disambiguate.)
>
> Thanks,
> Dave
>
>
> _______________________________________________
> PRL mailing list
> PRL at lists.ccs.neu.edu
> https://lists.ccs.neu.edu/bin/listinfo/prl
>