reserve k,m,n for Nat, kk,mm,nn for Element of NAT, X,Y,x,y,z for set;
reserve S,S1,S2 for Language, s,s1,s2 for Element of S;

theorem Th11: (AtomicFormulaSymbolsOf S) \ (RelSymbolsOf S)=TermSymbolsOf S
proof
set R=RelSymbolsOf S, SSS=AtomicFormulaSymbolsOf S, f=the adicity of S;
f"INT=SSS by FUNCT_2:40; hence SSS\R =
f"(INT\(INT\NAT)) by FUNCT_1:69.=
f"(INT\INT \/ (INT /\ NAT)) by XBOOLE_1:52
.= TermSymbolsOf S by XBOOLE_1:7, XBOOLE_1:28;
end;
