allow SimpleSymbolTable to use unanmed, internal variables (e.g., cardinality)
allow SimpleSymbolTable to use unanmed, internal variables (e.g., cardinality)

hoangmle/metaSMT,nbruns1/metaSMT,finnhaedicke/metaSMT,nbruns1/metaSMT,finnhaedicke/metaSMT,agra-uni-bremen/metaSMT,hoangmle/metaSMT,agra-uni-bremen/metaSMT,agra-uni-bremen/metaSMT,finnhaedicke/metaSMT,nbruns1/metaSMT,hoangmle/metaSMT