递归生成的加权移位算子的二次亚正规性

On Quadratically Hyponormal of Recursively Generated Weighted Shits

对于含有两个未知数的递归生成的加权移位算子,Jung提出了其二次亚正规和正的二次亚正规是等价的。但如果细加论证可以发现,这个假设是不正确的,对此有具体的实例可以证明。

For recursively generated weighted shift which have two unknown numbers, Jung considered that quadrati- cally hyponormal and positively quadratically hyponormal are equivalent. But the author proved that the conjecture is wrong. And last he gives an example.