Description: Lemma for dath . Frequently-used utility lemma. (Contributed by NM, 15-Aug-2012)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | da.ps0 | |- ( ps <-> ( ( c e. A /\ d e. A ) /\ -. c .<_ Y /\ ( d =/= c /\ -. d .<_ Y /\ C .<_ ( c .\/ d ) ) ) )  | 
					|
| da.a1 | |- A = ( Atoms ` K )  | 
					||
| Assertion | dalemcceb | |- ( ps -> c e. ( Base ` K ) )  | 
				
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | da.ps0 | |- ( ps <-> ( ( c e. A /\ d e. A ) /\ -. c .<_ Y /\ ( d =/= c /\ -. d .<_ Y /\ C .<_ ( c .\/ d ) ) ) )  | 
						|
| 2 | da.a1 | |- A = ( Atoms ` K )  | 
						|
| 3 | 1 | dalemccea | |- ( ps -> c e. A )  | 
						
| 4 | eqid | |- ( Base ` K ) = ( Base ` K )  | 
						|
| 5 | 4 2 | atbase | |- ( c e. A -> c e. ( Base ` K ) )  | 
						
| 6 | 3 5 | syl | |- ( ps -> c e. ( Base ` K ) )  |