Abstract
Hercules killed the Hydra of Lerna in a bloody battle—the second of the labor tasks imposed upon him in atonement for his hideous crimes. The Hydra was a horrible, aggressive mythological monster with many heads and poisonous blood, whose heads multiplied each time one of them was severed. This article explores some mathematical methods about this interesting epic battle. A generalization of the original Kirby & Paris model is proposed. We also study the connection of this model with Goodstein ultra-growing and recursive sequences. As an interesting application, we next analyze the inevitable death of another huge monster of our modern era: the Internet.
References
Goodstein, R. L. (1944) “On the restricted ordinal theorem”, Journal of Symbolic Logic 9: 33–41.
Ketonen, J.; Solovay, R. (1981) “Rapidly growing Ramsey functions”, Annals of Mathematics 113: 267–314.
Kirby, L.; Paris, J. (1982) “Accessible independence results for Peano arithmetic”, Bulletin of the London Mathematical Society 14: 285–293.
Loebl, M. (1988) “Hercules and Hydra”, Commentationes Mathematicae Univesitatis Carolinae 29(1), 85–95.
Luccio, F.; Pagli, L. (2000) “Death of a monster”, Pre-print, Departamento de Informática de la Universidad de Pisa, Italia.
Matousek, J.; Loebl, M. (1991) “Hercules versus hidden Hydra helper”, Commentationes Mathematicae Univesitatis Carolinae 32(4): 731–741.
Misercque, D. (1990) “Le plus long combat d’Hercule”, Bulletin de la Société Mathématique de Belgique 42, série B: 319–331.
Monk, D.J. (1969) Introduction to Set Theory. McGraw-Hill Book Company, New York.
Rogers, H. (1967) Theory of Recursive Functions and Effective Computability. McGraw-Hill Book Company, New York.