输入一个一阶语言，开头和结尾必须是括号。例如，(@a(P(a)).



数理逻辑的应用：通过C语言进行一阶语言的判断约束符号只限P,Q,R 变员符号只限a,b,c 命题符号为:&,|,~,-(蕴含),=(等价)



量词符号:全称量词:@ 存在量词:# -Enter a first order language must start and end brackets. For example, (@ a (P (a)). The application of mathematical logic: first-order through the C language sign language to judge bound only P, Q, R　become members of symbols restricted to a, b, c　proposition symbols :& ,|,~,-( implication), = (equal)　quantifier symbols: universal quantifier: @　existential quantifier:#