In finite volume, this factor can be identified as the total volume of space time.
These terms are then evaluated as fluxes at the surfaces of each finite volume.
Again we can sub-divide the spatial domain into finite volumes or cells.
They are not allowed in a finite volume with periodic or fixed boundary conditions.
As before, this only proves that the magnetization is zero at any finite volume.
For that matter, sometimes it is necessary to consider a finite arbitrary volume, called a control volume, over which these principles can be applied.
This finite volume is denoted by and its bounding surface .
Hadrons made of quarks need a finite proper volume growing with hadron mass.
This is called a "closed" universe, because it has finite spatial volume, but no boundary.
As above, one can also construct a more general formulation for integrals over a finite volume.