# Is it possible to multiply with a derivative operator?

**URL:** <https://discourse.julialang.org/t/is-it-possible-to-multiply-with-a-derivative-operator/28914>\
**Category:** General Usage\
**Created:** [September 18, 2019, 7:33pm UTC](https://discourse.julialang.org/t/is-it-possible-to-multiply-with-a-derivative-operator/28914 "2019-09-18T19:33:28Z")\
**Posts on this page:** 1\
**Showing post:** 22

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**Author:** ![chakravala](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chakravala/32/6832_2.png) [@chakravala](https://discourse.julialang.org/u/chakravala)\
**Post date:** [September 20, 2019, 3:33pm UTC](https://discourse.julialang.org/t/is-it-possible-to-multiply-with-a-derivative-operator/28914/22 "2019-09-20T15:33:23Z")

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> [@Ahmed\_Salih](#):
>
> This is in theory wrong, since an operator should not be applied on the expr to the left, but only to the right, so in approach 2, the result should have been `[2^x^3*∂ₓ,4*b*y*∂ᵧ,0]` - I know that matrix multiplication in Julia is able to handle such cases, so I just wondered, whether you would think that there is an easy way to get this behaviour in Julia?

In fact, I already have a solution work around for this; however, it is not yet fully implemented.

The solution is to use the differential forms and tensor fields… this is what I am working on implementing with the `Grassmann` package, for which the `Leibniz` is a mere prototype. Further development to fix this issue will be happening with `Grassmann` but it is not ready yet, as I have many other things in life.

It is not too difficult to implement and I already know how to do it, it’s simply a matter of taking the time to do it when I also have lots of other features and things in life to worry about too. The `Grassmann` package is going to have this built in properly. Not sure yet what I will do with maintaining the `Leibniz` package in the future… remember I am doing this work for free, please consider donating at [liberapay.com/chakravala](http://liberapay.com/chakravala)

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