+++ /dev/null
-!A:Prop.!B:Prop.!C:Prop.(and (sumbool A False) (and (or True B) (or B False))) -> True
-
-!A:Prop.!B:Prop.!C:Prop.(and (sumbool A C) (and (or A B) !D:Prop.(or B D))) -> True
-
-!A:Prop.!B:Prop.!C:Prop.(and (and A C) (and (and A B) (and B C))) -> True
-
-(and True True) -> True
-(and True False) -> True