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grothendieck_universe [2014/12/10 11:14]
nikolaj
grothendieck_universe [2015/08/24 19:32]
nikolaj
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 | @#55EE55: postulate ​  | @#55EE55: $Y \subseteq {\mathfrak G} \implies Y\ {\approx}\ {\mathfrak G}\lor Y \in {\mathfrak G} $ | | @#55EE55: postulate ​  | @#55EE55: $Y \subseteq {\mathfrak G} \implies Y\ {\approx}\ {\mathfrak G}\lor Y \in {\mathfrak G} $ |
  
-==== Discussion ​==== +----- 
-=== Formalities ​===+=== Discussion === 
 +== Formalities ==
 The symbol ${\approx}$ in the last postulate is an abbreviation. For subsets $Y$ of ${\mathfrak G}$, equinumerosity can be defined as the existence of a set of pairs, $f=\{\{y,​u\},​\{y',​u'​\},​\dots\}$,​ which puts elements $y\in Y$ uniquely in correspondence with $u\in{\mathfrak G}$: The symbol ${\approx}$ in the last postulate is an abbreviation. For subsets $Y$ of ${\mathfrak G}$, equinumerosity can be defined as the existence of a set of pairs, $f=\{\{y,​u\},​\{y',​u'​\},​\dots\}$,​ which puts elements $y\in Y$ uniquely in correspondence with $u\in{\mathfrak G}$:
  
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 nLab:  nLab: 
 [[http://​ncatlab.org/​nlab/​show/​Grothendieck+universe|Grothendieck universe]] [[http://​ncatlab.org/​nlab/​show/​Grothendieck+universe|Grothendieck universe]]
-==== Parents ====+ 
 +-----
 === Requirements === === Requirements ===
 [[Bijective function]], [[Power set]] [[Bijective function]], [[Power set]]
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