Metamath Proof Explorer


Theorem rpnnen3lem

Description: Lemma for rpnnen3 . (Contributed by Stefan O'Rear, 18-Jan-2015)

Ref Expression
Assertion rpnnen3lem a b a < b c | c < a c | c < b

Proof

Step Hyp Ref Expression
1 qbtwnre a b a < b d a < d d < b
2 simp2 a b a < b d a < d d < b d
3 simp3r a b a < b d a < d d < b d < b
4 breq1 c = d c < b d < b
5 4 elrab d c | c < b d d < b
6 2 3 5 sylanbrc a b a < b d a < d d < b d c | c < b
7 simp11 a b a < b d a < d d < b a
8 qre d d
9 8 3ad2ant2 a b a < b d a < d d < b d
10 simp3l a b a < b d a < d d < b a < d
11 7 9 10 ltnsymd a b a < b d a < d d < b ¬ d < a
12 11 intnand a b a < b d a < d d < b ¬ d d < a
13 breq1 c = d c < a d < a
14 13 elrab d c | c < a d d < a
15 12 14 sylnibr a b a < b d a < d d < b ¬ d c | c < a
16 nelne1 d c | c < b ¬ d c | c < a c | c < b c | c < a
17 6 15 16 syl2anc a b a < b d a < d d < b c | c < b c | c < a
18 17 necomd a b a < b d a < d d < b c | c < a c | c < b
19 18 rexlimdv3a a b a < b d a < d d < b c | c < a c | c < b
20 1 19 mpd a b a < b c | c < a c | c < b
21 20 3expa a b a < b c | c < a c | c < b