### BibTeX

@MISC{Akl05themyth,

author = {Selim G. Akl},

title = { THE MYTH OF UNIVERSAL COMPUTATION},

year = {2005}

}

### OpenURL

### Abstract

It is shown that the concept of a Universal Computer cannot be realized. Specifically, instances of a computable function F are exhibited that cannot be computed on any machine U that is capable of only a finite and fixed number of operations per step. This remains true even if the machine U is endowed with an infinite memory and the ability to communicate with the outside world while it is attempting to compute F. It also remains true if, in addition, U is given an indefinite amount of time to compute F. This result applies not only to idealized models of computation, such as the Turing Machine and the like, but also to all known general-purpose computers, including existing conventional computers, as well as contemplated ones such as quantum computers.