ex1:

lista_puncte([],_,[]).
lista_puncte([punct(X,Y)|T1], Val, [punct(X,Y)|Lrez]):- Y>Val, lista_puncte(T1, Val, Lrez).
lista_puncte([punct(_,Y)|T1], Val, Lrez):- Y=<Val, lista_puncte(T1, Val, Lrez).

ex2:

dropN(L, R, N) :- append(R, L1, L), length(L1, N).

ex3:

rmdn(Phi, Phi) :- atom(Phi).
rmdn(non(Phi), non(Phi)) :- atom(Phi).
rmdn(non(non(Phi)), Psi) :- rmdn(Phi, Psi).
rmdn(non(si(Phi,Psi)),non(A)) :- rmdn(si(Phi,Psi),A).
rmdn(non(sau(Phi,Psi)),non(A)) :- rmdn(sau(Phi,Psi),A).
rmdn(non(imp(Phi,Psi)),non(A)) :- rmdn(imp(Phi,Psi),A).
rmdn(si(Phi, Psi), si(Phi1, Psi1)) :- rmdn(Phi, Phi1), rmdn(Psi, Psi1).
rmdn(sau(Phi, Psi), sau(Phi1, Psi1)) :- rmdn(Phi, Phi1), rmdn(Psi, Psi1).
rmdn(imp(Phi, Psi), imp(Phi1, Psi1)) :- rmdn(Phi, Phi1), rmdn(Psi, Psi1).