Multitape simulation and model equivalence
A fixed finite-tape deterministic Turing machine running in time t(n)≥n can be simulated by a single-tape machine in O(t(n)²) time by storing tape contents and head markers and scanning them for each simulated step.
Key knowledge
A fixed finite-tape deterministic Turing machine running in time t(n)≥n can be simulated by a single-tape machine in O(t(n)²) time by storing tape contents and head markers and scanning them for each simulated step. These models have the same decidable languages and polynomial-time class.
Conditions and scope
- This is a specified classical machine-model simulation, not a proof about all imaginable physical computation.
- Same computability does not mean equal running time; bounded-cost arbitrary-size arithmetic must not be silently added.
Sources · 1
References
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Evidence and review
Lecture 12 slides 23–25 finite multitape/single-tape simulation and polynomial overhead.
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