Metamath Proof Explorer


Definition df-base

Description: Define the base set (also called underlying set, ground set, carrier set, or carrier) extractor for extensible structures. (Contributed by NM, 4-Sep-2011) (Revised by Mario Carneiro, 14-Aug-2015)

Ref Expression
Assertion df-base Base = Slot 1

Detailed syntax breakdown

Step Hyp Ref Expression
0 cbs Base
1 c1 1
2 1 cslot Slot 1
3 0 2 wceq Base = Slot 1