Metamath Proof Explorer


Theorem atssbase

Description: The set of atoms is a subset of the base set. ( atssch analog.) (Contributed by NM, 21-Oct-2011)

Ref Expression
Hypotheses atombase.b B=BaseK
atombase.a A=AtomsK
Assertion atssbase AB

Proof

Step Hyp Ref Expression
1 atombase.b B=BaseK
2 atombase.a A=AtomsK
3 1 2 atbase xAxB
4 3 ssriv AB