(VAR R T U V W) (RULES .(R,.(T,U)) -> .(.(R,T),U) .(R,id) -> R .(id,R) -> R and(id,id) -> id sub(id,id) -> id .(and(R,T),and(U,V)) -> and(.(R,U),.(T,V)) .(sub(R,T),sub(U,V)) -> sub(.(U,R),.(T,V)) .(and(R,T),w1) -> .(w1,R) .(and(R,T),w2) -> .(w2,T) .(R,c) -> .(c,and(R,R)) .(c,w1) -> id .(c,w2) -> id .(R,i) -> .(i,sub(id,and(R,id))) .(and(.(i,sub(id,R)),T),e) -> .(and(id,T),R) .(.(W,and(R,T)),and(U,V)) -> .(W,and(.(R,U),.(T,V))) .(.(W,sub(R,T)),sub(U,V)) -> .(W,sub(.(U,R),.(T,V))) .(.(W,and(R,T)),w1) -> .(.(W,w1),R) .(.(W,and(R,T)),w2) -> .(.(W,w2),T) .(and(i,R),e) -> and(id,R) .(.(W,and(i,R)),e) -> .(W,and(id,R)) .(.(W,and(.(i,sub(id,R)),T)),e) -> .(.(W,and(id,T)),R) ) (COMMENT Rules of Fig. 3 and Fig. 4 of \cite{BK08} doi: http://dx.doi.org/10.1007/978-3-540-89439-1_34 )