Bill Hesse and N. Immerman, Complete Problems for Dynamic Complexity Classes, LICS '02, 313-322.

Abstract: We present the first complete problems for dynamic complexity classes including the classes Dyn-FO and DynThC0, the dynamic classes corresponding to relational calculus and (polynomially bounded) SQL, respectively. The first problem we show complete for Dyn-FO is a single-step version of the circuit value problem (SSCV).

Of independent interest, our construction also produces a first-order formula, , that is in a sense universal for all first-order formulas. Since first-order formulas are stratified by quantifier depth, the first-order formula emulates formulas of greater depth by iterated application. As a corollary we obtain a fixed quantifier block, QBC, that is complete for all first-order quantifier blocks.

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