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Theorem

Savitch's Theorem

Logic and Foundations

Savitch's Theorem, proved by Walter Savitch in 1970, is a result of computational complexity theory stating that any problem a nondeterministic Turing machine can solve using f(n) space can also be solved by a deterministic Turing machine using space on the order of f(n) squared. It shows nondeterminism can inflate space usage by at most a quadratic factor, in sharp contrast to its apparently much larger effect on running time, and it implies that the complexity classes PSPACE and NPSPACE are equal, one of the few such class equalities known unconditionally.

Facts
Statement
For any space-constructible function f in Omega(log n), NSPACE(f(n)) is contained in DSPACE(f(n)^2). 2
Proof Year
1970 1
Classification
Statement Form
Inequality 1
Connections

Has Statement Form

Inequality, Concepts

Entity-backed identity for the statement-form enum value this theorem already carries, resolved to a mathematics concept by an explicit value-to-entity map (phase 3 bucket conversion, docs\design_entity_backed_browse_buckets_20260928.md). The statement-form fact itself stays on the theorem unchanged.

In Branch

Source Savitch's theorem, Wikipedia
Sources
1. Savitch's theorem (Wikipedia)
Wikipedia Savitch's theorem lead paragraph (w-bbfill-psymath4-0926)
Quote, Wikipedia Savitch's theorem lead paragraph (w-bbfill-psymath4-0926)
proved by Walter Savitch in 1970
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2. Savitch's theorem, Wikipedia
  • Lead paragraph
    for any space-constructible function f ∈ Ω(log(n)), NSPACE(f(n)) ⊆ DSPACE(f(n)²).
  • In Branch: Computational Complexity Theory, Lead sentence
    In computational complexity theory, Savitch's theorem, proved by Walter Savitch in 1970, gives a relationship between deterministi
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