An expression of the compactness theorem for sets of sentences is that: let T be a set of sentences in L. Then T has a model iff every finite subset of T has a model.(adsbygoogle = window.adsbygoogle || []).push({});

Could anyone give me some hints how to prove this?

The first direction is straightforward: every model of T is a model of every subset of T. But what about the opposite direction? Any help is appreciated!

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# Compactness theorem proof

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