引入不可否认签名的概念和模型，说明其存在的应用。
We introduce the notion and model of undeniable signature and show its applications available.
对于背包问题这样一个经典的递归问题，发现了它的不需栈支持的循环解法，并由此说明其存在并行。
For knapsack problem (which is a classical recursion problem), find its round solution which need not stack to support, then prove it exists parallel solutio.
对于背包问题这样一个经典的递归问题，发现了它的不需栈支持的循环解法，并由此说明其存在并行解。
For knapsack problem (which is a classical recursion problem), find its round solution which need not stack to support, then prove it exists parallel solution.
应用推荐