The positivity problem for fourth order linear recurrence sequences is decidable
Tom 128 / 2012
                    
                    
                        Colloquium Mathematicum 128 (2012), 133-142                    
                                        
                        MSC: Primary 11B37; Secondary 03D20.                    
                                        
                        DOI: 10.4064/cm128-1-11                    
                                    
                                                Streszczenie
The problem whether each element of a sequence satisfying a fourth order linear recurrence with integer coefficients is nonnegative, referred to as the Positivity Problem for fourth order linear recurrence sequence, is shown to be decidable.
 
             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                         
                                                            