Preservation of admissible rules when combining logics
  Admissible rules are shown to be conservatively preserved by the meet-combination of a wide class of logics. A basis is obtained for the resulting logic from bases given for the component logics. Structural completeness and decidability of the set of admissible rules are also shown to be preserved, the latter with no penalty on the time complexity. Examples are provided for the meet-combination of intermediate and modal logics. 
Joao Rasga and Cristina Sernadas and Amilcar Sernadas
math.LO