YES

Problem:
 first(0(),X) -> nil()
 first(s(X),cons(Y,Z)) -> cons(Y,n__first(X,activate(Z)))
 from(X) -> cons(X,n__from(s(X)))
 first(X1,X2) -> n__first(X1,X2)
 from(X) -> n__from(X)
 activate(n__first(X1,X2)) -> first(X1,X2)
 activate(n__from(X)) -> from(X)
 activate(X) -> X

Proof:
 DP Processor:
  DPs:
   first#(s(X),cons(Y,Z)) -> activate#(Z)
   activate#(n__first(X1,X2)) -> first#(X1,X2)
   activate#(n__from(X)) -> from#(X)
  TRS:
   first(0(),X) -> nil()
   first(s(X),cons(Y,Z)) -> cons(Y,n__first(X,activate(Z)))
   from(X) -> cons(X,n__from(s(X)))
   first(X1,X2) -> n__first(X1,X2)
   from(X) -> n__from(X)
   activate(n__first(X1,X2)) -> first(X1,X2)
   activate(n__from(X)) -> from(X)
   activate(X) -> X
  TDG Processor:
   DPs:
    first#(s(X),cons(Y,Z)) -> activate#(Z)
    activate#(n__first(X1,X2)) -> first#(X1,X2)
    activate#(n__from(X)) -> from#(X)
   TRS:
    first(0(),X) -> nil()
    first(s(X),cons(Y,Z)) -> cons(Y,n__first(X,activate(Z)))
    from(X) -> cons(X,n__from(s(X)))
    first(X1,X2) -> n__first(X1,X2)
    from(X) -> n__from(X)
    activate(n__first(X1,X2)) -> first(X1,X2)
    activate(n__from(X)) -> from(X)
    activate(X) -> X
   graph:
    activate#(n__first(X1,X2)) -> first#(X1,X2) ->
    first#(s(X),cons(Y,Z)) -> activate#(Z)
    first#(s(X),cons(Y,Z)) -> activate#(Z) ->
    activate#(n__from(X)) -> from#(X)
    first#(s(X),cons(Y,Z)) -> activate#(Z) -> activate#(n__first(X1,X2)) -> first#(X1,X2)
   SCC Processor:
    #sccs: 1
    #rules: 2
    #arcs: 3/9
    DPs:
     activate#(n__first(X1,X2)) -> first#(X1,X2)
     first#(s(X),cons(Y,Z)) -> activate#(Z)
    TRS:
     first(0(),X) -> nil()
     first(s(X),cons(Y,Z)) -> cons(Y,n__first(X,activate(Z)))
     from(X) -> cons(X,n__from(s(X)))
     first(X1,X2) -> n__first(X1,X2)
     from(X) -> n__from(X)
     activate(n__first(X1,X2)) -> first(X1,X2)
     activate(n__from(X)) -> from(X)
     activate(X) -> X
    Subterm Criterion Processor:
     simple projection:
      pi(first#) = 1
      pi(activate#) = 0
     problem:
      DPs:
       
      TRS:
       first(0(),X) -> nil()
       first(s(X),cons(Y,Z)) -> cons(Y,n__first(X,activate(Z)))
       from(X) -> cons(X,n__from(s(X)))
       first(X1,X2) -> n__first(X1,X2)
       from(X) -> n__from(X)
       activate(n__first(X1,X2)) -> first(X1,X2)
       activate(n__from(X)) -> from(X)
       activate(X) -> X
     Qed