REDUCTION TREE OF THE BINARY GENERALIZED POST CORRESPONDENCE PROBLEM

: Halava V, Holub S

Publisher: WORLD SCIENTIFIC PUBL CO PTE LTD

: 2011

: International Journal of Foundations of Computer Science

: INTERNATIONAL JOURNAL OF FOUNDATIONS OF COMPUTER SCIENCE

: INT J FOUND COMPUT S

: 2

: 22

: 2

: 473

: 490

: 18

: 0129-0541

DOI: https://doi.org/10.1142/S0129054111008143

An instance of the (Generalized) Post Correspondence Problem is during the decision process typically reduced to one or more other instances, called its successors. In this paper we study the reduction tree of GPCP in the binary case. This entails in particular a detailed analysis of the structure of end blocks. We give an upper bound for the number of end blocks, and show that even if an instance has more than one successor, it can nevertheless be reduced to a single instance. This, in particular, implies that binary GPCP can be decided in polynomial time.