Does anyone knows why it is impossible to obtain an odd order equation of motion from a Lagrangian? I recently heard that, but I can't find a nice discussion anywhere.(adsbygoogle = window.adsbygoogle || []).push({});

It is also interesting to note that this might not even valid for field theory, take as an example the Schrodinger equation which can indeed be retrieved from a Lagrangian and is of odd order (because of the first order time derivative), anyone has an idea of why this happens? I mean why we can't get an odd order equation of motion for discrete system with n degrees of freedom but we can get it for some field (which obviously has infinite degrees of freedom).

Thanks in advance.

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# Odd order motion equations from a Lagrangian

Can you offer guidance or do you also need help?

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