  This letter reports theory of elasticity and hydrodynamics of quasicrystals
with 7-, 14-, 9- and 18-fold symmetries in solid phase, in which the
6-dimensional embedding space concept is used. Based on the concept and the
Landau-Anderson symmetry breaking principle and the Lubensky hydrodynamics, the
governing equations for the above quasicrystal systems have been set up, the
solving procedure for the initial-boundary value problems of the equations is
discussed as well. Though the discussion is concerned only for the
quasicrystals, in particular for one of 18-fold symmetry, in solid phase, it
may be a basis for those in soft matter phase observed recently.
