Question

What should i make for working model in science and maths?Plzzz tell.

Answer 1

I think , you work it ! best modal !
One example that I know of is something called provability logic. This is a kind of modal logic in which the alethic operator for necessity is interpreted as an operator for provability. This is used mainly for proving results about self-referential statements in arithmetic. 

It is often referred to as GL, after its founders, Kürt Gödel and Martin Hugo Löb. One arrives at GL by starting with system K. System K, named after Saul Kripke, is often used as a foundation for more extensive modal logics, i.e. more 'rules' are added to those of system K. 

By adding axiom GL to system K, which is also known as Löb's Theorem, one gets system GL: □(□A →A) → □A. Note that the necessity operator is interpreted as a provability operator (this is not a trivial change!), so the statement means that, (in a theory with Peano arithmetic), if it is provable that if P is provable then P is true, then P is provable. 

If you would like to read more on this, I would recommend the excellent article on the SEP on