Talk:Weakly compact cardinal
Latest comment: 10 months ago by C7X in topic "A relatively convoluted definition"
"A relatively convoluted definition"
In my opinion as I've been working more with infinitary languages, it seems like the compactness property of weakly compact cardinals is not very complicated. The compactness theorem already admits some extensions, with the most attention directed to what to replace the word "finite" in the compactness theorem with.
Then there is only one major change between the compactness theorem and the weak compactness property:
- When Γ is a set of Lω,ω-sentences of size <ℵ0, if every subset of Γ of size <ℵ0 has a model, then Γ has a model.
- When Γ is a set of Lκ,κ-sentences of size <κ, if every subset of Γ of size <κ has a model, then Γ has a model.
where the change is the italicized part. C7X (talk) 21:15, 29 August 2023 (UTC)