Hello, Is Lagrangian invariant? I am in a conversation, where one is saying that: "Shifting the coordinate system changes the value of the potential energy with respect to the same reference level, that's why the Lagrangian changes" While the other: "Shifting the coordinate system, doesnt shift the zero reference level of potential for the system.. The reference level of potential is fixed for the system once it is decided upon." So, is Lagrangian variant or invariant? Please help. Thanks.