RT Journal T1 Judgement of a-Weyls theorem and its perturbations A1 KONG Ying-ying, CAO Xiao-hong, DAI Lei PB JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE) FD 2017-10-20 YR 2017 JF JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE) JO JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE) VO 52 IS 10 SP 77 DO 10.6040/j.issn.1671-9352.0.2017.187 K1 a-Weyls theorem;approximate point spectrum;compact perturbation LK {http://lxbwk.njournal.sdu.edu.cn/EN/article/article_2620.shtml}