I Partial derivative is terms of Kronecker delta and the Laplacian operator

[Safinaz]

TL;DR Summary

How to write partial derivatives in terms of Kronecker delta and the Laplacian operator?

How can the following term:

$T_{ij} = \partial_i \partial_j \phi$

to be written in terms of Kronecker delta and the Laplacian operator $\bigtriangleup = \nabla^2$?

I mean is there a relation like:

$T_{ij} = \partial_i \partial_j \phi = ?? \delta_{ij} \bigtriangleup \phi.$

But what are ?? term

Any help is appreciated!

 

[Orodruin]

It cannot.

 

[Safinaz]

It cannot.

So there is no any way to simplify $\partial_i \partial_j \phi$ ?

 

[Orodruin]

Not really no. Not without knowing more. In some special cases, perhaps, but not as a general rule.

What is the context here?