Metamath Proof Explorer


Theorem nfwrd

Description: Hypothesis builder for Word S . (Contributed by Mario Carneiro, 26-Feb-2016)

Ref Expression
Hypothesis nfwrd.1
|- F/_ x S
Assertion nfwrd
|- F/_ x Word S

Proof

Step Hyp Ref Expression
1 nfwrd.1
 |-  F/_ x S
2 df-word
 |-  Word S = { w | E. l e. NN0 w : ( 0 ..^ l ) --> S }
3 nfcv
 |-  F/_ x NN0
4 nfcv
 |-  F/_ x w
5 nfcv
 |-  F/_ x ( 0 ..^ l )
6 4 5 1 nff
 |-  F/ x w : ( 0 ..^ l ) --> S
7 3 6 nfrex
 |-  F/ x E. l e. NN0 w : ( 0 ..^ l ) --> S
8 7 nfab
 |-  F/_ x { w | E. l e. NN0 w : ( 0 ..^ l ) --> S }
9 2 8 nfcxfr
 |-  F/_ x Word S