third time asking this question. Any answers with structure and broad explanation will be accepted.

Compare the following macro economic models in terms of Real Costs of Reducing Inflation :

1) -The Keynesian Model.

2) -The Monetarist Model.

3) -The New Classical Model.

Compare these three models in terms of the theoretical structure (assumptions, hypotheses, etc.)

Why, for some models, can the real costs of lowering inflation be so high while in others be lower or zero ?