Unifying Ghost-Free Lorentz-Invariant Lagrangians

Understand

We present the details of the novel framework for Lagrangian field theories that are Lorentz-invariant and lead to at most second order equations of motion.

• The use of antisymmetric structure is of crucial importance.
• The general ghost-free Lagrangians are constructed and then translated into the language of differential forms.
• The ghost-freeness has a geometric nature.