a1:=ex**t(cross(ma(c,5),ma(c,10)),3);a2:=ex**t(cross(ma(c,5),ma(c,20)),3);a3:=cross(ma(c,10),ma(c,20));a4:=ma(c,20)>=ref((ma(c,20)),1);三军会师:a1 and a2 and a3... 20210311
1)xg:ma(c,5)>ref(ma(c,5),1) and ma(c,10)>ref(ma(c,10),1) and ma(c,20)>ref(ma(c,20),1) and ma(c,30)>ref(ma(c,30),1) and c>o and ref(c,1)>ref(o,1) and ref(c,2)>ref(o,2) and c>ma(...