Extremely High Energy and Violation of Lorentz Invariance
  Extremely high-energy(EHE) cosmic rays might provide a chance to check a violation of the Lorentz symmetry of spacetime. Some theoretical consideration is described about why the Lorentz symmetry might break-down in EHE phenomena in this universe. Some models which introduce the violation of the Lorentz symmetry will be discussed. 
Humitaka Sato