1Despite the social emphasis in Multi-Agent Based Systems research, individual agent control systems (ACS) can not be discarded. The individual capacity for effective action selection and enforcement require agents with harmonised real-time and long-term capabilities. Neither the reactive nor deliberative paradigms seem to provide this harmony. We are proposing an ACS schema where longterm cond...

The hard square model in statistical mechanics has been investigated for the case when the activity z is −1. For cyclic boundary conditions, the characteristic polynomial of the transfer matrix has an intriguingly simple structure, all the eigenvalues x being zero, roots of unity, or solutions of x 3 = 4 cos 2 (πm/N). Here we tabulate the results for lattices of up to 12 columns with cyclic or ...

We consider the system of N (≥ 2) hard balls with masses m1, . . . , mN and radius r in the flat torus TL = R /L · Z of size L, ν ≥ 3. We prove the ergodicity (actually, the Bernoulli mixing property) of such systems for almost every selection (m1, . . . , mN ; L) of the outer geometric parameters. This theorem complements my earlier result that proved the same, almost sure ergodicity for the c...

This paper considers steganography – the concept of hiding the presence of secret messages in legal communications – in the computational setting and its relation to cryptography. Very recently the first (non-polynomial time) steganographic protocol has been shown which, for any communication channel, is provably secure, reliable, and has nearly optimal bandwidth. The security is unconditional,...

We prove exponential lower bounds on the resolution proofs of some tautologies, based on rectangular grid graphs. More specifically, we show a 2Ω(n) lower bound for any resolution proof of the mutilated chessboard problem on a 2n× 2n chessboard as well as for the Tseitin tautology based on the n×n rectangular grid graph. The former result answers a 35 year old conjecture by McCarthy.

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In constraint logic programming (CLP) systems, the standard technique for dealing with hard constraints is to delay solving them until additional constraints reduce them to a simpler form. For example, the CLP(R) system delays the solving of nonlinear equations until they become linear, when certain variables become ground. In a naive implementation , the overhead of delaying and awakening cons...

This paper shows that it is computationally hard to decide (or test) whether a consumption data set is consistent with separable preferences.