Re: [Groff] Why does tty-char.tmac not represent meaning?

[G. Branden Robinson]

At 2017-06-25T02:40:52+0200, Ingo Schwarze wrote:
> > But "gradient", by picking out one meaning of several
> > (gradient, divergence, laplacian)
> 
> I have never seen the "nabla" symbol used for "laplacian".
> The Laplacian is the scalar product of the gradient with
> itself, or equivalently, the divergence of the gradient.
> The Laplacian is a scalar, while both "grad" and "div" are
> first order tensors.
> 
> So, for the Laplacian, we have
> 
>   \(*D = \(gr \(pc \(gr
> 
> but the "nabla" symbol itself is never called "laplacian"
> as far as i can tell.

The only conventions I've seen for the laplacian are "nabla squared" and
(capital) "delta" (never spoken that way), i.e., turning the symbol
upside down again.

However, I am not formally trained in tensor analysis and have not seen
a lot of its literature.

Apart from that, I wanted to add my +1 to your proposal.

Regards,
Branden

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