id: 01021715 dt: j an: 01021715 au: Németi, István ti: Strong representability of fork algebras, a set theoretic foundation. so: Log. J. IGPL 5, No.1, 3-23 (1997). py: 1997 pu: Oxford University Press, Oxford la: EN cc: ut: fork algebra; relation algebra; anti-foundation axiom; representation theorem; equational theory; fork operation; finitization problem; non-well-founded set theory ci: li: doi:10.1093/jigpal/5.1.3 ab: The aim of the author is to show that there is a particular not well-founded set theory (an extension of ZF + AC $-$ Axiom of Foundation by a certain anti-foundation axiom) in which a particular class of abstract fork algebras defined by finitely many equations admits a strong representation theorem: every algebra from the class is isomorphic to a set relation algebra with a “concrete” (i.e. set theoretically defined) fork operation. This is a refined result, for it fails to be provable in more usual set theories or with respect to other known variants of concreteness of fork. The author also discusses some related results concerning the finitization problem in algebraic and in pure first-order logic. The introductory section contains a brief history of the subject, with a great many of references. rv: Jānis Cīrulis (Riga)