of: a partial differential equation which has a separable solution, and which can be rearranged to produce an equation whose left-hand and right-hand sides involve different independent variables
is: a constant that can be equated to either side of the final equation described above, since the two sides of the equation are independent yet equal, so they must both be equal to the same constant. [M6.4]
is exemplified: by the constant 
that arises when the one-dimensional time-dependent Schrödinger equation, with time-independent potential energy 
and separable stationary state solution 
is rewritten to yield two ordinary differential equations (one of them the time-independent Schrödinger equation) for the spatial and temporal parts of the wavefunction. [M6.4]
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