Quantization on the light-front provides the rigorous field-theoretical realization of the intuitive ideas of the parton model which is formulated at fixed t in the infinite-momentum frame. (see #Infinite momentum frame). The same results are obtained in the front form for any frame; e.g., the structure functions and other probabilistic parton distributions measured in deep inelastic scattering are obtained from the squares of the boost-invariant light-front wave functions, the eigensolution of the light-front Hamiltonian. The Bjorken kinematic variable x b j of deep inelastic scattering becomes identified with the light-front fraction at small x . The Balitsky–Fadin–Kuraev–Lipatov (BFKL) Regge behavior of structure functions can be demonstrated from the behavior of light-front wave functions at small x . The Dokshitzer–Gribov–Lipatov–Altarelli–Parisi (DGLAP) evolution of structure functions and the Efremov–Radyushkin–Brodsky–Lepage (ERBL) evolution of distribution amplitudes in log ⁡ ⁡ Q 2 are properties of the light-front wave functions at high transverse momentum.