论文标题
希格曼的引理更强大，以获得更好的准订单
Higman's lemma is stronger for better quasi orders
论文作者
论文摘要
我们证明，在反向数学的框架内，希格曼的引理严格来说，比准订单更强大。实际上，我们显示出更强的结果：无限的Ramsey定理（适用于各个长度的元素）从陈述中说，任何数组$ [\ Mathbb n]^{n+1} \ to \ Mathbb n^n \ times x $ for polder of prod $ x $ and y Mathbb in \ mathbb n $ base base base $ base $ base $ base $ base base $ base base $ base base base base $ base base base base base $ \ c。
We prove that Higman's lemma is strictly stronger for better quasi orders than for well quasi orders, within the framework of reverse mathematics. In fact, we show a stronger result: the infinite Ramsey theorem (for tuples of all lengths) follows from the statement that any array $[\mathbb N]^{n+1}\to\mathbb N^n\times X$ for a well order $X$ and $n\in\mathbb N$ is good, over the base theory $\mathsf{RCA_0}$.
