Re: Re: Prefix function syntax f @ x

*To*: mathgroup at smc.vnet.net*Subject*: [mg66678] Re: [mg66651] Re: [mg66638] Prefix function syntax f @ x*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Sat, 27 May 2006 03:50:51 -0400 (EDT)*Organization*: Mathematics & Statistics, Univ. of Mass./Amherst*References*: <200605250658.CAA03726@smc.vnet.net> <200605260817.EAA01716@smc.vnet.net>*Reply-to*: murray at math.umass.edu*Sender*: owner-wri-mathgroup at wolfram.com

Of course @, as in f @ g, is remarkably similar to the traditional mathematical symbol (a small circle) for function composition. So using f@g[x] in place of f[g[x]]] ought not to be that "non-standard". Actually, it's non-standard from the viewpoint of mathematical notation in one respect: Let me use o to stand for the traditional mathematical small circle (in TeX: \circ). Then (f o g)(x) by definition means f(g(x))). In Mathematica, by contrast, (f@g)[x] does NOT mean the same thing as f[g[x]]. For example: f[x_] := x^2 g[x_] := x + 5 (f@g)[x] // FullForm Power[g, 2][x] Andrzej Kozlowski wrote: > On 25 May 2006, at 15:58, Kristen W Carlson wrote: > >> Hi, >> >> David Wagner emphasizes that he doesn't use the syntax >> function@argument (p. 37n), no explanation. To me it seems very handy. >> Any thoughts? > > > I also never use it (although until I now have never considered why). > I guess the reason must be is that f[x] or f(x) is the standard > mathematical notation for the value of a function f at x and I am > used to it. I don't have this problem with @@, /@ or even @@@ > probably because these are programming constructs that do not > correspond to any standard mathematical concepts. > > Andrzej Kozlowski > Tokyo, Japan > > -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305

**References**:**Prefix function syntax f @ x***From:*"Kristen W Carlson" <carlsonkw@gmail.com>

**Re: Prefix function syntax f @ x***From:*Andrzej Kozlowski <akoz@mimuw.edu.pl>