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Definition df-aleph 7541
Description: Define the aleph function. Our definition expresses Definition 12 of [Suppes] p. 229 in a closed form, from which we derive the recursive definition as theorems aleph0 7661, alephsuc 7663, and alephlim 7662. The aleph function provides a one-to-one, onto mapping from the ordinal numbers to the infinite cardinal numbers. Roughly, any aleph is the smallest infinite cardinal number whose size is strictly greater than any aleph before it. (Contributed by NM, 21-Oct-2003.)
Assertion
Ref Expression
df-aleph  |-  aleph  =  rec (har ,  om )

Detailed syntax breakdown of Definition df-aleph
StepHypRef Expression
1 cale 7537 . 2  class  aleph
2 char 7238 . . 3  class har
3 com 4628 . . 3  class  om
42, 3crdg 6390 . 2  class  rec (har ,  om )
51, 4wceq 1619 1  wff  aleph  =  rec (har ,  om )
Colors of variables: wff set class
This definition is referenced by:  alephfnon  7660  aleph0  7661  alephlim  7662  alephsuc  7663
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