(VAR x y z) (RULES and(x,or(y,z)) -> or(and(x,y),and(x,z)) and(x,and(y,y)) -> and(x,y) or(or(x,y),and(y,z)) -> or(x,y) or(x,and(x,y)) -> x or(true,y) -> true or(x,false) -> x or(x,x) -> x or(x,or(y,y)) -> or(x,y) and(x,true) -> x and(false,y) -> false and(x,x) -> x ) (COMMENT Example 4.21 (Distributive Lattices) in \cite{SK90})