----- Original Message ----
> From: Tracy Harms <[EMAIL PROTECTED]>
> To: [email protected]
> Sent: Tuesday, September 16, 2008 11:23:24 AM
> Subject: [Jchat] The unifying generalization of derivatives
>
> I found a series of blog postings by Conal Elliott on the
> generalization of derivatives. Others may also enjoy them, so here's
> the URI:
>
> http://conal.net/blog/
>
> Perhaps most interesting is the one entitled "Higher-dimensional,
> higher-order derivatives, functionally". In that posting the chain
> rule is given by the following expression:
>
> deriv (f . g) x = deriv f (g x) . deriv g x
>
Incorrect form: the first "." is composition, the second
should be multiplication. The composition on the right
side should be between f' and first g.
> I'm confused by the use of composition on the right-hand side, as I
> expect it to involve two functions. I can't see a composition of two
> functions here; in J terms, I see nouns where I expect verbs.
> Guidance in correcting my misinterpretation is welcome.
>
> Tracy
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