Why should physical theories always have a Lagrangian formalism?
44282
How do I show that there exists variational/action principle for a given classical system?
36380
Why not use the Lagrangian, instead of the Hamiltonian, in nonrelativistic QM?
114672
Why do we use the Lagrangian and Hamiltonian instead of other related functions?
48068
Any good resources for Lagrangian and Hamiltonian Dynamics?
17588
Can Lagrangian be thought of as a metric?
18054
Is there a proof from the first principle that the Lagrangian L = T - V?
131016
Question about Klein-Gordon field Lagrangian
146853
Do we need inertial frames in Lagrangian mechanics?
94173
Deriving the Lagrangian for a free particle
112209
Landau's argument for dependence of Lagrangian on magnitude of velocity
121584
Rigor in quantum field theory
120529
Relations between diffeomorphism symmetry theories and invariant $SU(N), N \rightarrow \infty$ theories
94433
Rigorous underpinnings of infinitesimals in physics
99312
Why Lagrangian is negative number for a relativistic massive point particle?
109187
The differences between Lagrange and Leibniz's derivative notations
129289
What is the origin of the factor of $-1/4$ in the Maxwell Lagrangian?
27296
Derivation of Lagrangian of electromagnetic field from Lorentz force