# [om] Q: Content Dictionary calculus1, partialdiff

Matthias Berth berth at uni-greifswald.de
Fri Jul 30 13:59:18 CEST 1999

Hello,

I have questions regarding the definition of partial derivatives in the
calculus1 CD:

http://www.nag.co.uk/projects/openmath/corecd/html/cd/calculus1.html#partialdiff

There is an example

In TeX:      \partial^2{xyz}/\partial{x}\partial{z}
In OpenMath: partialdiff(list(1,3), lambda[x y z].(times(x,y,z)))(y)

As far as I understand it, here partialdiff is applied to an operator,
giving another operator, which is then applied to y.

My first question is: Shouldn't the result of the differentiation be an
operator of the same "signature", taking three arguments, not just one
(y)?

My second question is: How is the PDE u_xx+x*u_t=0 expressed using
partialdiff?

Thanks,

Matthias

Matthias Berth
berth at uni-greifswald.de
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