Combining Texts

Ideas for 'Unconscious Cerebral Initiative', 'New Foundations for Mathematical Logic' and 'Elucidation of some points in E.Schrder'

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2 ideas

4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set

14238

A class is an aggregate of objects; if you destroy them, you destroy the class; there is no empty class [Frege]

4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets

9879	NF has no models, but just blocks the comprehension axiom, to avoid contradictions [Quine, by Dummett]