chapter  5
i–Algebras, i–Frames and Heyting Algebras
Pages 6

T his follows from p m(->->(xAy)) = - - ( p m(x )n p m(y)) = p (p m(x )n p m(y)) =

/, , Pm(x ) n /, , p m(y) = Pm(_,'ix) n Pra("i“’y) = p m(“'_'xA “'_'y) by ( n ) and from Pm(~1_,(xVy)) = — (Pm(x ) uPm(y)) = - ( - p m(x ) n - p m(y)) = - ( p m(“’x ) n p ra(-'y) = p m(-i(“'xA-iy)) by (3). The explicit L M -derivations I presented as 4 .(1 ) - (4).