discrete? Seriously? What kind of a tag is that? Too broad .
Discrete means as opposed to continuous.
For, instance, people may ask questions about discrete electric charges, discrete spacetime, discrete energies, etc.
If discretization is vital/essential to the question then tag it with the discrete tag.
Currently there is 37 questions tagged with the discrete tag.
A related tag (in case of quantum theory) is the quantization tag.