Combining Texts

Ideas for 'Causation', 'Reply to 'Rorarius' 2nd ed' and 'Introduction to Mathematical Logic'

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3 ideas

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

17752

The empty set is useful for defining sets by properties, when the members are not yet known [Walicki]

17753

The empty set avoids having to take special precautions in case members vanish [Walicki]

4. Formal Logic / F. Set Theory ST / 6. Ordering in Sets

17759

Ordinals play the central role in set theory, providing the model of well-ordering [Walicki]