Set theory

Scott's trick

In set theory, Scott's trick is a method for giving a definition of equivalence classes for equivalence relations on a proper class (Jech 2003:65) by referring to levels of the cumulative hierarchy. The method relies on the axiom of regularity but not on the axiom of choice. It can be used to define representatives for ordinal numbers in ZF, Zermelo–Fraenkel set theory without the axiom of choice (Forster 2003:182). The method was introduced by Dana Scott. Beyond the problem of defining set representatives for ordinal numbers, Scott's trick can be used to obtain representatives for cardinal numbers and more generally for isomorphism types, for example, order types of linearly ordered sets (Jech 2003:65). It is credited to be indispensable (even in the presence of the axiom of choice) when taking ultrapowers of proper classes in model theory. (Kanamori 1994:47) (Wikipedia).

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Huge Finger Board Trick!

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From playlist Funny Videos, Parodies, Odds and ends!

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Magic Tricks with a Mobile Phone Tutorial 1

Just a magic trick that involves using a phone :) Followed by a full tutorial on how to do it! Phone trick 2: https://www.youtube.com/watch?v=EJyWPANoO9k Magic playlist: https://www.youtube.com/playlist?list... Mind reading playlist: https://www.youtube.com/playlist?list...

From playlist Magic

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From playlist My Magic

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From playlist Magic

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From playlist Magic Tricks

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cool watch the whole thing it very cool at the end...

From playlist Interesting Videos

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This is my entry to Ericsurf6's contest. http://www.youtube.com/watch?v=yYlHLoGqNT0 Find me on FaceBook: http://www.facebook.com/pages/YouTube-TyYanns-page/130204640380067

From playlist Other...

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From playlist Magic

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From playlist Magic

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From playlist Celebration of Mind 2021

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From playlist EngageNY Grade 3 Module 5

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From playlist Teacher Tips: Zoom Meeting & Google Drive (Online Learning)

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From playlist 100…(102!) Years of the Ising Model

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From playlist Fail Lab by Zoochosis

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From playlist Recent Google Calendar "How To" Training

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From playlist Stupid Physics Tricks

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From playlist Concrete Problems in AI Safety

Related pages

Isomorphism class | Bijection | The Higher Infinite | Axiom of regularity | Equivalence class | Cumulative hierarchy | Model theory | Order type | Set theory | Ordinal number | Aleph number | Zermelo–Fraenkel set theory