[om] Q: Content Dictionary calculus1, partialdiff

[Matthias Berth]

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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