找到原文，和tiers 定义了

原文：

https://download.ssrn.com/2025/11/6/5425555.pdf?response-content-disposition=inline&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEJL%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaCXVzLWVhc3QtMSJHMEUCIQDmsD0bgc%2FHvv9mWQ6HGKFrpJb46nWZxOcipfWi3ZbOnwIgAujFA4oImOSMrRmuEoP5j%2F4QlYEg2jWzrVFm7Y9sibEqvQUIWxAEGgwzMDg0NzUzMDEyNTciDF0oIIsiMVlQXbsnUSqaBf2DdoOqstHfv10j89uunpTrz2YzHj0eUXvOi7Uu4YAcKOfScersZeOlEVLzpxOjLZ7Qb%2FEGen%2BvxDa9nkjIKAxwEdXh49vK8DxQ8%2FoOHm4vKdSMxNvqz1l1PEJGT7jnlipLzz3Ik%2FU73XIO4cFtj67eauIGLVt5yki85j9%2BVVmFWxQAdwguq6ANhWTLm4J4lHkWzQuXsb6CPKKTAOtOQ4%2FwNRVUWoFCByLNUa5s%2Bg9GouNxsM8wEBCuqfVVSXUdtFQV313hxIT48SzEiJWikCDalMBN1PlFyBrlZSrigCnZLjNWJmnG5fj%2FCB0dAHQGbqCQGjdMByoCvGZPJci34ELVE%2BHG6Yk42H1QgNIRF%2FetqMHDR5TeEk7lUb9ylP2uipIo%2BtJKWb6Lre%2BA3gQWYxfYwn9zkd%2FurdL7tYIOmKGXFeVbbQ0NCk0Snb%2F9Neib61ZKS4MNN2d8zzpgcfA8OnIAtA2zMYV%2B9iW63%2FLUV0cHwTk4KyZhvMbVPUMq6A%2FW14JeA1pv9uWSi5FWqLs9w4bJR3PuKFd3ebjY3BuNXFK%2FynvWhDEi5iHJcVxVXv9od%2F5vCPwJbTEb5FqY7Dd8mDR7zPpM5zehZNpQ203mI03sqeMK5ciYY%2Fmah7wTnqDg1fUB0mHH9T4vPLviKGd9mRMIzGH%2F7mOQZkvXK3ilB3bznp%2Fuuidek4D%2FmsGSxrtxHSY7QJ59uqb4nkTbfwCUaR4JNiu%2Fp%2Bk2segA6gxkJsL9WKvOxEkE66aHUz%2Fg4BHkgm0xVPnQ1KlOSvz2075Y%2F%2FTdmQQtscLrWvhvsRjzt6ow%2FsUzu%2FzMWMUL0wkWX4UQG0d1hmBsxBZkoHrP01iMtKhIa3d1AbzY3LMgb2ryghCnqPOPPXXp3T7IWDCMj9rIBjqxAZNEGEX3rc7rt4H1lbvubUlPs4UDme9ayBe675pKFwxh2jN0%2BffNILAy%2FGW2pwlaMy%2FKsF0SbZ4VgsxPjHGhnaUsg2D8ZCzyx7uRC1NW59eYLWgKL%2FZAZYF62TKfCmksS6uLBHRiM%2Fdbn4r4jge1gz3xBSGUUgQ%2FyXxUlopfOQOojt9NL0tUyxSpPLb%2BEhd8SjtsdIJBJEThcYLgZUicqQXLfR%2Fris7O%2FKOxJU0zAn8bKQ%3D%3D&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20251114T022933Z&X-Amz-SignedHeaders=host&X-Amz-Expires=300&X-Amz-Credential=ASIAUPUUPRWE7PMRNNOY%2F20251114%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Signature=30853bfecf38413ed51448e6995a4a8a5c342ef29c6a96f62ed432ef71bb963d&abstractId=5425555