Reduced products and nonstandard logics
Miroslav Benda · Journal of Symbolic Logic · 1969
The results of the present paper were announced in [1]. The work is divided into our parts. In the first part we define relations (relations between relational struc tures) and we show their connection with the equivalence of the languages LΚ,λ (Theorem 1). The relations generalize the games Gn (n < ω) of Ehrenfeucht (see [2]) and the conditions (i)–(ii) which were used by Karp in [5].