Do Schrödinger's equations include the principle of least action?
Any time-dependent physical process must conform to the principle of least action which is a universal law.
We assume that the Schrödinger PDE SE solution in its current form does not automatically follow the principle of least action, but some mathematicians and physicists argue that it should if the terms of the SE and PLA concepts are extended or modified.
On the other hand, the chain mechanics of matrix B in its spontaneous form intrinsically contains the principle of least action and in addition the normalization condition.