Quantum-mechanical vector property in solid-state physics
There are an infinite number of sinusoidal oscillations that perfectly fit a set of discrete oscillators, making it impossible to define a k-vector unequivocally. This is a relation of inter-oscillator distances to the spatial Nyquist frequency of waves in the lattice.[1] See also Aliasing § Sampling sinusoidal functions for more on the equivalence of k-vectors.