Metamath Proof Explorer

Theorem basendx

Description: Index value of the base set extractor. (Normally it is preferred to work with ( Basendx ) rather than the hard-coded 1 in order to make structure theorems portable. This is an example of how to obtain it when needed.) (New usage is discouraged.) (Contributed by Mario Carneiro, 2-Aug-2013)

Ref Expression
Assertion basendx Base ndx = 1


Step Hyp Ref Expression
1 df-base Base = Slot 1
2 1nn 1
3 1 2 ndxarg Base ndx = 1