Metamath Proof Explorer

Theorem baseid

Description: Utility theorem: index-independent form of df-base . (Contributed by NM, 20-Oct-2012)

Ref Expression
Assertion baseid 
|- Base = Slot ( Base ` ndx )

Proof

Step Hyp Ref Expression
1 df-base 
 |-  Base = Slot 1
2 1nn 
 |-  1 e. NN
3 1 2 ndxid 
 |-  Base = Slot ( Base ` ndx )