Combining Texts

Ideas for 'works', 'Symbolic Reasoning' and 'Higher-Order Logic'

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2 ideas

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

21548

The null class is the class with all the non-existents as its members [MacColl, by Lackey]

4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX

10301

The axiom of choice is controversial, but it could be replaced [Shapiro]