Exercise · ZW-GODELS-INCOMPLETENESS-007 · ★★☆ Intermediate

An undecidable sentence is one that...

Choose one option.

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  • B. Can be neither proved nor refuted within the system

Explanation

An undecidable sentence is one that the system can neither prove nor refute, even though it is well formed.

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Review the concept: Gödel’s incompleteness

A consistent system \(\mathcal{S}\) that represents enough arithmetic is incomplete: there is a formula \(\varphi\) that it can neither prove nor refute.

\[\\exists\\varphi\\,(\\mathcal{S}\\nvdash\\varphi\\land\\mathcal{S}\\nvdash\\neg\\varphi)\]

More practice problems: gödel’s incompleteness

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