通达信壶底买入选股指标公式

EXIST(DOWNNDAY(V,4),13) AND EXIST(NDAY(V,REF(V,1),4),7) AND EXIST(DOWNNDAY(C,3),13)
AND EXIST(NDAY(C,REF(C,1),3),7) AND EXIST(LLV(C,20),7);