# Part II

Ghost-free Massive Gravity

6 Massive, Bi- and Multi-Gravity Formulation: A Summary

7 Evading the BD Ghost in Massive Gravity

7.1 ADM formulation

7.2 Absence of ghost in the Stückelberg language

7.3 Absence of ghost in the vielbein formulation

7.4 Absence of ghosts in multi-gravity

8 Decoupling Limits

8.1 Scaling versus decoupling

8.2 Massive gravity as a decoupling limit of bi-gravity

8.3 Decoupling limit of massive gravity

8.4 -decoupling limit of bi-gravity

9 Extensions of Ghost-free Massive Gravity

9.1 Mass-varying

9.2 Quasi-dilaton

9.3 Partially massless

10 Massive Gravity Field Theory

10.1 Vainshtein mechanism

10.2 Validity of the EFT

10.3 Non-renormalization

10.4 Quantum corrections beyond the decoupling limit

10.5 Strong coupling scale vs cutoff

10.6 Superluminalities and (a)causality

10.7 Galileon duality

7 Evading the BD Ghost in Massive Gravity

7.1 ADM formulation

7.2 Absence of ghost in the Stückelberg language

7.3 Absence of ghost in the vielbein formulation

7.4 Absence of ghosts in multi-gravity

8 Decoupling Limits

8.1 Scaling versus decoupling

8.2 Massive gravity as a decoupling limit of bi-gravity

8.3 Decoupling limit of massive gravity

8.4 -decoupling limit of bi-gravity

9 Extensions of Ghost-free Massive Gravity

9.1 Mass-varying

9.2 Quasi-dilaton

9.3 Partially massless

10 Massive Gravity Field Theory

10.1 Vainshtein mechanism

10.2 Validity of the EFT

10.3 Non-renormalization

10.4 Quantum corrections beyond the decoupling limit

10.5 Strong coupling scale vs cutoff

10.6 Superluminalities and (a)causality

10.7 Galileon duality