效绵鼎 Productions A production has the form variable (head)->string of variables and terminals (body) Convention: o A,B.C....and also S are variables. 0 a,b,c,...are terminals. ...X,Y,Z are either terminals or variables. ...w,x,y,z are strings of terminals only. 0 a,B,y,...are strings of terminals and/or variables 8Productions ◼ A production has the form variable (head) -> string of variables and terminals (body). ◼ Convention:  A, B, C,… and also S are variables.  a, b, c,… are terminals.  …, X, Y, Z are either terminals or variables.  …, w, x, y, z are strings of terminals only.  , , ,… are strings of terminals and/or variables. 8