%% predicates
% succ(N1,N2) -- N1 = N2 - 1 (Peano's successor)

% lt(N1,N2) -- N1 < N2

!- mode(succ(+,-)).
!- mode(lt(+,+)).

lt(0,2).
lt(1,3).
lt(2,4).
lt(3,5).
lt(4,6).
lt(5,7).
lt(6,8).
lt(7,9).
lt(8,10).
lt(9,11).

lt(0,3).
lt(1,4).
lt(2,5).
lt(3,6).
lt(4,7).
lt(5,8).

lt(0,1).
lt(1,2).
lt(2,3).
lt(3,4).
lt(4,5).
lt(5,6).
lt(6,7).
lt(7,8).
lt(8,9).
lt(9,10).
lt(10,11).
lt(11,12).
lt(12,13).
lt(13,14).
lt(14,15).
lt(15,16).
lt(16,17).
lt(17,18).
lt(18,19).
lt(19,20).
lt(20,21).
lt(21,22).
lt(22,23).
lt(23,24).
lt(24,25).
lt(25,26).
lt(26,27).
lt(27,28).
lt(28,29).
lt(29,30).
lt(30,31).
lt(31,32).
lt(32,33).
lt(33,34).
lt(34,35).
lt(35,36).
lt(36,37).
lt(37,38).
lt(38,39).
lt(39,40).
lt(40,41).
lt(41,42).
lt(42,43).
lt(43,44).
lt(44,45).
lt(45,46).
lt(46,47).
lt(47,48).
lt(48,49).
lt(49,50).

succ(0,1).
succ(1,2).
succ(2,3).
succ(3,4).
succ(4,5).
succ(5,6).
succ(6,7).
succ(7,8).
succ(8,9).
succ(9,10).
succ(10,11).
succ(11,12).
succ(12,13).
succ(13,14).
succ(14,15).
succ(15,16).
succ(16,17).
succ(17,18).
succ(18,19).
succ(19,20).
succ(20,21).
succ(21,22).
succ(22,23).
succ(23,24).
succ(24,25).
succ(25,26).
succ(26,27).
succ(27,28).
succ(28,29).
succ(29,30).
succ(30,31).
succ(31,32).
succ(32,33).
succ(33,34).
succ(34,35).
succ(35,36).
succ(36,37).
succ(37,38).
succ(38,39).
succ(39,40).
succ(40,41).
succ(41,42).
succ(42,43).
succ(43,44).
succ(44,45).
succ(45,46).
succ(46,47).
succ(47,48).
succ(48,49).
succ(49,50).