>>13820489>like wise then what is empty set and two empty sets can be different?It depends on your axiomatic system.
Generally, set theorists use an axiomatic system that includes a rule called "the axiom of extension"; where extension is used in a niche way. If i define a set S1 as the "set of even primes", and I define a set S2 as the "set containing the first even positive integer". Well S1 = {2} and S2 = {2}. In this case, S1 and S2 are defined differently, they have different intensions, but they have the same members, so they have the same extensions.
The axiom of extension means that any two sets with the exactly the same members are the same set.
So two empty sets, though they may have been defined differently, are the same by the axiom of extension
