Thanks for replying.
I'm confused about two things.
(1) I'm worried I haven't explained myself well.
I mean I want to find all x given g(x) is true for some function g.
i.e. the set { x | g(x) is true }
(You may have answered this, I need to read your example more carefully, but
this leads me to problem 2...)
(2) I don't understand what
←→
means in terms of J. These are not ASCII characters or J primitives.
Thanks.
> Date: Fri, 26 Dec 2014 08:13:40 -0800
> From: [email protected]
> To: [email protected]
> Subject: Re: [Jprogramming] "Such that" syntax in J
>
> f x
>
> where x is an array of all values of interest. For (countably) infinite
> sets you have to express x in terms of i._ . For example, to express the
> Euler product formula for the Riemann zeta function,
>
> +/(1+i._)^-s ←→ */%1-(p:i._)^-s
>
>
>
> On Fri, Dec 26, 2014 at 8:04 AM, Jon Hough <[email protected]> wrote:
> >
> > In Haskell (and other languages I'm sure) one can express the idea of
> > "such that" to denote one expression depending on another. In Haskell we
> > can use the syntax:
> >
> > [ f x | x <- xs ]
> >
> > which means
> > "the list of all f x
> > such that x is drawn from xs."
> >
> > So | is syntactically similar to the English "such that". (and very much
> > like | in mathematical sets)
> >
> > I would like to know if J has a construct to express the above Haskell
> > code.
> >
> > Thanks,
> > Jon.
> >
> > ----------------------------------------------------------------------
> > For information about J forums see http://www.jsoftware.com/forums.htm
> >
> ----------------------------------------------------------------------
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