Metamath Proof Explorer


Theorem basfn

Description: The base set extractor is a function on _V . (Contributed by Stefan O'Rear, 8-Jul-2015)

Ref Expression
Assertion basfn
|- Base Fn _V

Proof

Step Hyp Ref Expression
1 baseid
 |-  Base = Slot ( Base ` ndx )
2 1 slotfn
 |-  Base Fn _V