Our model of computation (theoretical machine) was designed for the analysis of analog Fourier optical processors, its basic data unit being a continuous image of unbounded resolution. In this paper, we demonstrate the universality of our machine by presenting a framework for arbitrary Turing machine simulation. Computational complexity bene ts are also demonstrated by providing a O(log2n) algo...

Turing showed the existence of a model universal for the set of Turing machines in the sense that given an encoding of any Turing machine as input the universal Turing machine simulates it. We introduce the concept of univer-sality for reactive systems and construct a ccs process universal in the sense that, given an encoding of any ccs process, it behaves like this process up to weak bisimulat...

We present an improved simulation of space and reversal bounded Turing machines by width and depth bounded uniform circuits. (All resource bounds hold simultaneously.) An S(n) space, R(n) reversal bounded deterministic k-tape Turing machine can be simulated by a uniform circuit of O(R(n) log2S(n)) depth and O(S(n) k) width. Our proof is cleaner, and has slightly better resource bounds than the ...

We associate the iterated block product of a bimachine with a deterministic Turing machine. This allows us to introduce new algebraic notions to study the behavior of the Turing machine. Namely, we introduce double semidirect products through matrix multiplication of upper triangular matrices with coefficients in certain semigroups, which leads in turn to the study of the iterations of bimachin...