We characterize the polynomial time computable queries as those ex pressible in relational calculus plus a least xed point operator and a total ordering on the universe We also show that even without the ordering one application of xed point su ces to express any query expressible with several alternations of xed point and negation This proves that the xed point query hierarchy suggested by Cha...

In order to solve domain equations over 1-bounded compact metric spaces, xed points of functors on categories of 1-bounded compact metric spaces are studied. Two categories of 1-bounded compact metric spaces are considered: KMS and KMS E. In both categories, objects are isomorphic if and only if they are isometric. As a consequence, provided that the operation of a domain equation can be extend...

In the bus network problem, the goal is to generate a plan for getting from point X to point Y within a city using buses in the smallest expected time. Because bus arrival times are not determined by a xed schedule but instead may be random, the problem requires more than standard shortest path techniques. In recent work, Datar and Ranade provide algorithms in the case where bus arrivals are as...

Diiusion processes on the Sierpinski gasket and the abc-gaskets are constructed as limits of random walks. In terms of the associated renor-malization group, the present method uses the inverse trajectories which converge to unstable xed points corresponding to the random walks on one-dimensional chains. In particular, non-degenerate xed points are unnecessary for the construction. A limit theo...

We present a treatment for mathematical economists of three topics in the theory of xed points: (a) the Lefschetz xed point index; (b) the Lefschetz xed point theorem; (c) the theory of essential sets of xed points. Our treatment is geometric, based on elementary techniques, and largely selfcontained. In particular there is no essential reference to algebraic topology. Within the chosen scope o...

Induction for Horn clauses from data received a major boost from the success of FOIL 1;2;3 as a pioneer clausal learning algorithm. FOIL attempts to explain a target relation (while avoiding a negative set) by incrementally adding clauses that successively increase this explained part. The residue of the target set is obtained by postulating the target set in the antecedents (body) of the gener...

an idea of fuzzy reexivity of felbin's type fuzzy normed linear spaces is introduced and its properties are studied. concept of fuzzy uniform normal structure is given and using the geometric properties of this concept xed point theorems are proved in fuzzy normed linear spaces.

Proof systems with sequents of the form U ` for proving validity of a propositional modal-calculus formula over a set U of states in a given model usually handle xed-point formulae through unfolding, thus allowing such formulae to reappear in a proof. Tagging is a technique originated by Winskel for annotating xed-point formulae with information about the proof states at which these are unfolde...

We evaluate by Monte Carlo simulations various singular thermodynamic quantities X, for an ensemble of quenched random Ising and Ashkin-Teller models. The measurements are taken at T c and we study how the distributions P(X) (and, in particular, their relative squared width, R X) over the ensemble depend on the system size l. The Ashkin-Teller model was studied in the regime where bond randomne...

This report extends the technique of testing single variance components with generalized xed{level tests | in situations when nuisance parameters make exact testing impossible | to the more general way of testing hypotheses on linear forms of variance components. An extension of the deenition of a generalized test variable leads to a generalized xed{level test for arbitrary linear hypotheses on...