We investigate the conservation laws of the conformable fractional modified Korteweg–de Vries (mKdV) equation, in which the temporal derivative of order $ \alpha $ and the spatial derivatives of orders $ \beta_0, \beta_1, \beta_2, \beta_3 $ are all taken in the conformable sense. Our main result provides a complete classification of all conservation laws of this equation whose characteristics have order at most $ 3 $. We show that the four most fundamental conservation laws of the classical mKdV equation, i.e., the mass, momentum, energy, and Galilean conservation laws, admit conformable counterparts, and we determine the precise conditions on the spatial orders $ \beta_0, \beta_1, \beta_2, \beta_3 $ under which each counterpart holds. We also establish that, under these conditions, the conformable conservation laws provide a complete classification in the same sense as the classical case. The conserved densities and fluxes are written out explicitly, and their physical interpretations as conformable mass, momentum, energy, and centre of momentum are discussed.
Citation: Nan Wangyu, Qiao Xin, Yang Jiang. Conformable mass, momentum, energy, and Galilean conservation laws of the conformable modified Korteweg-de Vries equation[J]. AIMS Mathematics, 2026, 11(10): 32920-32944. doi: 10.3934/math.20261291
We investigate the conservation laws of the conformable fractional modified Korteweg–de Vries (mKdV) equation, in which the temporal derivative of order $ \alpha $ and the spatial derivatives of orders $ \beta_0, \beta_1, \beta_2, \beta_3 $ are all taken in the conformable sense. Our main result provides a complete classification of all conservation laws of this equation whose characteristics have order at most $ 3 $. We show that the four most fundamental conservation laws of the classical mKdV equation, i.e., the mass, momentum, energy, and Galilean conservation laws, admit conformable counterparts, and we determine the precise conditions on the spatial orders $ \beta_0, \beta_1, \beta_2, \beta_3 $ under which each counterpart holds. We also establish that, under these conditions, the conformable conservation laws provide a complete classification in the same sense as the classical case. The conserved densities and fluxes are written out explicitly, and their physical interpretations as conformable mass, momentum, energy, and centre of momentum are discussed.
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