Integrate by parts the d'alembertian of a 4-variable function

[radoo]

Can you please tell me how to integrate by parts the d'alembertian of a 4-variable function over a volume dx * dy * dz * dt. I have stumbled upon this seemnigly simple exercise on my way to understanding QFT of scalar fields.

 

[dextercioby]

Why don't you post your integral, so we can see what it's all about ?