Combining Texts

Ideas for 'fragments/reports', 'Lectures on Aesthetics' and 'On Second-Order Logic'

unexpand these ideas     |    start again     |     choose another area for these texts

display all the ideas for this combination of texts

---

1 idea

6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / e. Peano arithmetic 2nd-order

10833	Many concepts can only be expressed by second-order logic [Boolos]
	Full Idea: The notions of infinity and countability can be characterized by second-order sentences, though not by first-order sentences (as compactness and Skolem-Löwenheim theorems show), .. as well as well-ordering, progression, ancestral and identity.
	From: George Boolos (On Second-Order Logic [1975], p.48)