YES(?,O(1))
* Step 1: UnsatRules WORST_CASE(?,O(1))
    + Considered Problem:
        Rules:
          0. start(A) -> a(A)   [A >= 1]                         (1,1)
          1. start(A) -> a(A)   [A >= 2]                         (1,1)
          2. start(A) -> a(A)   [A >= 4]                         (1,1)
          3. a(A)     -> a(A*B) [1 >= 2*B && 3*B >= 2 && A >= 2] (?,1)
        Signature:
          {(a,1);(start,1)}
        Flow Graph:
          [0->{3},1->{3},2->{3},3->{3}]
        
    + Applied Processor:
        UnsatRules
    + Details:
        Following transitions have unsatisfiable constraints and are removed:  [3]
* Step 2: UnsatPaths WORST_CASE(?,O(1))
    + Considered Problem:
        Rules:
          0. start(A) -> a(A) [A >= 1] (1,1)
          1. start(A) -> a(A) [A >= 2] (1,1)
          2. start(A) -> a(A) [A >= 4] (1,1)
        Signature:
          {(a,1);(start,1)}
        Flow Graph:
          [0->{},1->{},2->{}]
        
    + Applied Processor:
        UnsatPaths
    + Details:
        The problem is already solved.

YES(?,O(1))