Description: Lemma for alephfp . (Contributed by NM, 6-Nov-2004)
Ref | Expression | ||
---|---|---|---|
Hypothesis | alephfplem.1 | |- H = ( rec ( aleph , _om ) |` _om ) |
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Assertion | alephfplem2 | |- ( w e. _om -> ( H ` suc w ) = ( aleph ` ( H ` w ) ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | alephfplem.1 | |- H = ( rec ( aleph , _om ) |` _om ) |
|
2 | frsuc | |- ( w e. _om -> ( ( rec ( aleph , _om ) |` _om ) ` suc w ) = ( aleph ` ( ( rec ( aleph , _om ) |` _om ) ` w ) ) ) |
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3 | 1 | fveq1i | |- ( H ` suc w ) = ( ( rec ( aleph , _om ) |` _om ) ` suc w ) |
4 | 1 | fveq1i | |- ( H ` w ) = ( ( rec ( aleph , _om ) |` _om ) ` w ) |
5 | 4 | fveq2i | |- ( aleph ` ( H ` w ) ) = ( aleph ` ( ( rec ( aleph , _om ) |` _om ) ` w ) ) |
6 | 2 3 5 | 3eqtr4g | |- ( w e. _om -> ( H ` suc w ) = ( aleph ` ( H ` w ) ) ) |