= Classical computation
<Classical computation> processes information described by classical <states> and transition rules, in contrast with computations that use coherent <quantum states>. A digital classical model commonly represents data by <bits>; a <Boolean circuit> or <Turing machine> supplies rules for transforming those representations. A <randomized algorithm> adds random choices, while each particular execution still follows one sequence of classical <states>.
For example, an <AND gate> maps two <bits>[input bits] to one <bit>[output bit], with output one only for input `11`. A probabilistic selection between two inputs describes uncertainty about which classical <state> was used; it is not a coherent <quantum superposition> of those inputs. Stating the model separates the abstract information-processing rule from its physical implementation: ordinary electronic devices ultimately obey quantum physics even when their exposed computational behavior is classical.
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