Exam questions from "Model theory":

Academic year 2020/21: you will get a question chosen randomly from the following list.

  • (1) The completeness theorem (its precise statement), the compactness theorem and a proof of the latter from the former.
    Applications of the compactness theorem: constructions of non-standard models of the ring of integers and of the ordered real closed field, a proof of the Ax-Grothedieck theorem on injective polynomial maps on the field of complex numbers.

  • (2) Skolemization of a theory and the Lowenheim-Skolem theorem. Vaught's test and its applications to theories DLO, ACF_p and to the theory of vector spaces over the field of rationals. From completeness to decidability for recursive theories.

  • (3) Countable categoricity of DLO, the Ehrenfeucht-Fraisse games and elementary equivalence of structures. The theory of random graphs and the 0-1 law for first-order logic on finite graphs.

  • (4) Quantifier elimination and its proofs for DLO and ACF. The strong minimality of ACF and the o-minimality of RCF (assuming QE for RCE).

  • (5) Types, saturated structures and their properties and existence (an example construction via ultraproduct). Omitting types theorem and MacDowell-Specker theorem (without proofs).