From: Tobias Nipkow <nipkow@in.tum.de>
Tree Enumeration
Nils Cremer
This thesis presents the verification of enumeration algorithms for trees. The 
first algorithm is based on the well known Prüfer-correspondence and allows the 
enumeration of all possible labeled trees over a fixed finite set of vertices. 
The second algorithm enumerates rooted, unlabeled trees of a specified size up 
to graph isomorphism. It allows for the efficient enumeration without the use of 
an intermediate encoding of the trees with level sequences, unlike the algorithm 
by Beyer and Hedetniemi it is based on. Both algorithms are formalized and 
verified in Isabelle/HOL. The formalization of trees and other graph theoretic 
results is also presented.
https://www.isa-afp.org/entries/Tree_Enumeration.html
Enjoy!
From: Tobias Nipkow <nipkow@in.tum.de>
Tree Enumeration
Nils Cremer
This thesis presents the verification of enumeration algorithms for trees. The 
first algorithm is based on the well known Prüfer-correspondence and allows the 
enumeration of all possible labeled trees over a fixed finite set of vertices. 
The second algorithm enumerates rooted, unlabeled trees of a specified size up 
to graph isomorphism. It allows for the efficient enumeration without the use of 
an intermediate encoding of the trees with level sequences, unlike the algorithm 
by Beyer and Hedetniemi it is based on. Both algorithms are formalized and 
verified in Isabelle/HOL. The formalization of trees and other graph theoretic 
results is also presented.
https://www.isa-afp.org/entries/Tree_Enumeration.html
Enjoy!
Last updated: Oct 31 2025 at 12:44 UTC