The husk and stray are counted as sub-variants of existing mobs as opposed to entirely new mobs, hence why you are unable to simply type /summon Stray or /summon Husk. There was supposed to be spawn eggs for them, but it seems they were removed either intentionally or by accident in the final release.
Axiomatic method, in logic, a procedure by which an entire system (e.g., a science) is generated in accordance with specified rules by logical deduction from certain basic propositions (axioms or postulates), which in turn are constructed from a few terms taken as primitive.
1 major reference (in foundations of mathematics: The axiomatic method) 2  analysis in metalogic (in metalogic: The axiomatic method) 3  formal logic (in philosophy of logic: Limitations of logic)  history of logic (in history of logic: Logical semantics and model theory)