良序性与数学归纳法原理 First Principle of Mathematical Induction.Let S(n)be a statement about integers for n E N and suppose S(no)is true for some integer no.If for all integers k with k no S(k)implies that S(k+1)is true,then S(n) is true for all integers n greater than no. Second Principle of Mathematical Induction.Let S(n)be a statement about integers for n EN and suppose S(no)is true for some integer no.If S(no),S(no+1),...,S(k)imply that S(+1)for k no,then the statement S(n)is true for all integers n greater than no. Principle of Well-Ordering.Every nonempty subset of the natural num- bers is well-ordered.良序性与数学归纳法原理