Reason behind $L = T - V$ (Lagrangian formalism)
18054
Is there a proof from the first principle that the Lagrangian L = T - V?
114672
Why do we use the Lagrangian and Hamiltonian instead of other related functions?
120474
Does the lagrangian contain all the information about the representations of the fields in QFT?
64727
Total time derivatives and partial coordinate derivatives in classical mechanics
73045
Transitioning between Lagrangian and Eulerian fluid variables
94230
I want to understand a trick in the derivation of the Schwinger-Dyson equations
83917
How can I prove that the following Lagrangian is Lorentz-invariant iff the axionic field is a pseudoscalar?
10785
Form of the Classical EM Lagrangian
126142
Action principle, Lagrangian mechanics, Hamiltonian mechanics, and conservation laws when assuming Aristotelian mechanics $F=mv$
156234
Why is the Converse to Lagrange's Theorem False?
44239
Why the extra term $\frac{1}{2}(\partial_{\rho}A^{\rho})^2$ in the photon Lagrangian?
46053
How to find Hamiltonian from this simple Lagrangian? (tricky)
4283
Trouble understanding Landau & Lifshitz writing about Lagrangians and Galilean Relativity
112187
Is there a way to see that $ \nabla_\mu g_{\nu \rho} = 0 $ without explicit computation, where $\nabla_\mu$ refers to the covariant derivative?
82135
Lagrangian to Hamiltonian in Quantum Field Theory
27016
Is the Lagrangian density a functional or a function?
66939
Picturing the how the covariant derivative acts on vector fields