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sav08:preliminary_discussion_on_models [2008/03/20 11:22] vkuncak |
sav08:preliminary_discussion_on_models [2008/03/20 13:40] vkuncak |
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Are there first-order formulas that have only infinite models? | Are there first-order formulas that have only infinite models? | ||
- | What is the cardinality of the models we need to consider? There are many useful models whose domains is not a [[countable set]]. | + | What is the cardinality of the models we need to consider? There are many useful models whose domain is not a [[countable set]]. |
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+ | Difficulty in checking $\models S$: there are infinitely many models, of arbitrarily large cardinalities. | ||
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+ | Goal: show that if a set $S$ of formulas has a model, then it has a particular kind, and this model is countable. |