Hidden Local Symmetry and the Vector Manifestation of Chiral Symmetry in Hot and/or Dense Matter

The emergence and importance of hidden local symmetry in the structure of hadrons under extreme conditions is discussed. The topics covered are the potentially important role played by an infinite tower of vector mesons encoded in holographic dual QCD (or AdS/QCD) in chiral dynamics of mesons and baryons, in the vector dominance and its violation in EW response functions and the presence of the vector manifestation fixed point and its influence on the properties of hadrons in hot temperature (i.e., in relativistic heavy ion collisions) and in dense matter (i.e., in compact stars). Also discussed are the natural emergence of instantons/skyrmions from the infinite tower of vector mesons coupled to pions in AdS/QCD and their (speculated) role in chiral restoration at high density.