Source: wikibot/barwise-compactness-theorem
= Barwise compactness theorem
{wiki=Barwise_compactness_theorem}
The Barwise Compactness Theorem is a result in model theory, specifically concerning first-order logic and structures. It extends the concept of compactness, which states that if every finite subset of a set of first-order sentences has a model, then the entire set has a model. The Barwise Compactness Theorem applies this idea to certain kinds of structures known as "partial structures.