Successor set
Set
context | $X$ |
definiendum | $ {\mathrm{succ}}\ X \equiv X \cup \{X\} $ |
Discussion
Theorems
$ X\in {\mathrm{succ}}\ X $ |
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$ ({\mathrm{succ}}\ X={\mathrm{succ}}\ Y)\Rightarrow (X=Y) $ |
$ (Y\in {\mathrm{succ}}\ X)\Leftrightarrow (Y=X\lor Y=\{X\}) $ |
$ X\neq {\mathrm{succ}}\ X $ |
Reference
Wikipedia: Successor ordinal
ProofWiki: Successor set