We define reactive simulatability for general asynchronous systems. Roughly, simulatability means that a real system implements an ideal system (specification) in a way that pre...
We show that 2-tag systems efficiently simulate Turing machines. As a corollary we find that the small universal Turing machines of Rogozhin, Minsky and others simulate Turing ma...
Maurer machines are much closer to real computers than Turing machines. Computer instructions play a prominent part in Maurer machines. We show a straightforward way to simulate Tu...
ABSTRACT. In this note we prove that any Turing machine which uses only a finite computational space for every input cannot solve an uncomputable problem even in case it runs in a...