作者Jer1983 (stanley)
看板logic
标题[请益] axiom system
时间Sat Jan 17 21:14:38 2009
各位好, 小弟最近在研读Mendelson的introduction to mathematical logic.
目前看到第一章第四节, 在谈formal axiomatic thoery L.
其中有一段说 If A,B and C are any wfs(well-formed formulas) of L,
then the following are axioms of L:
(A1) ( A => (B => A) )
(A2) ( (A => (B => C)) => ((A => B) => (A => C)) )
(A3) ( ((┐B) => (┐A)) => (((┐B) => A) => B) )
实在不懂作者想表达的意思...这里的axiom指的是公理吗? 比方说实数系的公理那种?
还有就是well-formed formulas, 请问版上有人可以用数学的例子说明吗?
thanks in advance.
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