Graph Isomorphism is in the Low Hierarchy

It is shown that the graph isomorphism problem is located in the low hierarchy in NP. This implies that this problem is not NPcomplete (not even under weaker forms of polynomial-time reducibilities, such as y-reducibility) unless the polynomial-time hierarchy collapses.

• Type: Conference
• Year: 1987
• Where: STACS
• Authors: Uwe Schöning
• Keywords: Graph Isomorphism Problem, Low Hierarchy, Polynomial-time Hierarchy Collapses, STACS 1987, Theoretical Computer Science