for S being Language holds
( (LettersOf S) /\ (OpSymbolsOf S) = {} & (TermSymbolsOf S) /\ (LowerCompoundersOf S) = OpSymbolsOf S & (RelSymbolsOf S) \ (OwnSymbolsOf S) = {(TheEqSymbOf S)} & OwnSymbolsOf S c= AtomicFormulaSymbolsOf S & RelSymbolsOf S c= LowerCompoundersOf S & OpSymbolsOf S c= TermSymbolsOf S & LettersOf S c= TermSymbolsOf S & TermSymbolsOf S c= OwnSymbolsOf S & OpSymbolsOf S c= LowerCompoundersOf S & LowerCompoundersOf S c= AtomicFormulaSymbolsOf S )