Metamath Proof Explorer


Theorem preimagelt

Description: The preimage of a right-open, unbounded below interval, is the complement of a left-closed unbounded above interval. (Contributed by Glauco Siliprandi, 26-Jun-2021)

Ref Expression
Hypotheses preimagelt.x x φ
preimagelt.b φ x A B *
preimagelt.c φ C *
Assertion preimagelt φ A x A | C B = x A | B < C

Proof

Step Hyp Ref Expression
1 preimagelt.x x φ
2 preimagelt.b φ x A B *
3 preimagelt.c φ C *
4 nfcv _ x A
5 nfrab1 _ x x A | C B
6 4 5 nfdif _ x A x A | C B
7 nfrab1 _ x x A | B < C
8 eldifi x A x A | C B x A
9 8 adantl φ x A x A | C B x A
10 eldifn x A x A | C B ¬ x x A | C B
11 8 anim1i x A x A | C B C B x A C B
12 rabid x x A | C B x A C B
13 11 12 sylibr x A x A | C B C B x x A | C B
14 10 13 mtand x A x A | C B ¬ C B
15 14 adantl φ x A x A | C B ¬ C B
16 8 2 sylan2 φ x A x A | C B B *
17 3 adantr φ x A x A | C B C *
18 16 17 xrltnled φ x A x A | C B B < C ¬ C B
19 15 18 mpbird φ x A x A | C B B < C
20 rabid x x A | B < C x A B < C
21 9 19 20 sylanbrc φ x A x A | C B x x A | B < C
22 rabidim1 x x A | B < C x A
23 22 adantl φ x x A | B < C x A
24 rabidim2 x x A | B < C B < C
25 24 adantl φ x x A | B < C B < C
26 22 2 sylan2 φ x x A | B < C B *
27 3 adantr φ x x A | B < C C *
28 26 27 xrltnled φ x x A | B < C B < C ¬ C B
29 25 28 mpbid φ x x A | B < C ¬ C B
30 29 intnand φ x x A | B < C ¬ x A C B
31 30 12 sylnibr φ x x A | B < C ¬ x x A | C B
32 23 31 eldifd φ x x A | B < C x A x A | C B
33 21 32 impbida φ x A x A | C B x x A | B < C
34 1 6 7 33 eqrd φ A x A | C B = x A | B < C