Count of parentheses 「The eorem Every well-formed proposition has the same number of left as right parentheses O Consider the symbols without parentheses first O And then prove it by induction with more complicated propositions according to the DefinitionCount of Parentheses . Theorem . . Every well-formed proposition has the same number of left as right parentheses. . Proof. . . 1. Consider the symbols without parentheses first. 2. And then prove it by induction with more complicated propositions according to the Definition. Yi Li (Fudan University) Discrete Mathematics(II) March 26, 2013 6 / 20