Direct Product Testers and PCPs from Coset Complexes

Explore direct product testers and probabilistically checkable proofs (PCPs) through the lens of algebraically-defined Kaufman–Oppenheim (KO) complexes in this computer science and discrete mathematics seminar. Learn how direct-product testers function as crucial components in PCP design, which forms the foundation of modern complexity theory and cryptography. Discover the elementary and strongly explicit description of KO complexes and understand their direct-product testability properties in the low-soundness regime. Examine how this research answers an open question posed by Kaufman–Oppenheim–Weinberger and demonstrates that KO complexes can generate PCPs with arbitrarily small constant soundness and quasilinear length. Compare these findings with previous results from Chapman–Lubotzky's construction that required sophisticated number theory and algebraic group theory tools, while KO complexes offer a more accessible approach. Gain comprehensive understanding of direct-product testing concepts and KO complex structures, with the presentation requiring only basic knowledge of probability and group theory as prerequisites.