Title :
The 0-1 law fails for the class of existential second order Godel sentences with equality
Author :
Pacholski, Leszek ; Szwast, Wieslaw
Author_Institution :
Inst. of Math., Polish Acad. of Sci., Wroclaw, Poland
fDate :
30 Oct-1 Nov 1989
Abstract :
P. Kolaitis and M. Vardi (see Proc. 19th ACM Symp. on Theory of Computing, p.425-35 (1987), and Proc. 3rd Ann. Symp. on Logic in Computer Science, p.2-11 (1988)) proved that the 0-1 law holds for the second-order existential sentences whose first-order parts are formulas of Bernays-Schonfinkel or Ackermann prefix classes. They also provided several examples of second-order formulas for which the 0-1 law does not hold and noticed that the classification of second-order sentences for which the 0-1 law holds resembles the classification of decidable cases of prenex first-order sentences. The only cases they have not settled were the cases of Godel classes with and without equality. The authors confirm the conjecture of Kolaitis and Vardi that the 0-1 law does not hold for the existential second-order sentences whose first-order part is in the godel prenex form with equality
Keywords :
decidability; formal logic; 0-1 law; Ackermann prefix classes; Bernays-Schonfinkel; decidable cases; prenex first-order sentences; second order Godel sentences; Application software; Combinatorial mathematics; Complexity theory; Computer science; Logic; Out of order; Upper bound;
Conference_Titel :
Foundations of Computer Science, 1989., 30th Annual Symposium on
Conference_Location :
Research Triangle Park, NC
Print_ISBN :
0-8186-1982-1
DOI :
10.1109/SFCS.1989.63472