Machines Equivalent To The Turing Machine Model
Turing equivalence
Many machines that might be thought to have more computational capability than a simple universal Turing machine can be shown to have no more power (Hopcroft and Ullman p. 159, cf Minsky). They might compute faster, perhaps, or use less memory, or their instruction set might be smaller, but they cannot compute more powerfully (i.e. more mathematical functions). (The Church-Turing thesis hypothesizes this to be true: that anything that can be “computed” can be computed by some Turing machine.)
The sequential-machine models
All of the following are called "sequential machine models" to distinguish them from "parallel machine models" (van Emde Boas (1990) p. 18).
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