Metamath Proof Explorer


Theorem noinfdm

Description: Next, we calculate the domain of T . This is mostly to change bound variables. (Contributed by Scott Fenton, 8-Aug-2024)

Ref Expression
Hypothesis noinfdm.1 T = if x B y B ¬ y < s x ι x B | y B ¬ y < s x dom ι x B | y B ¬ y < s x 1 𝑜 g y | u B y dom u v B ¬ u < s v u suc y = v suc y ι x | u B g dom u v B ¬ u < s v u suc g = v suc g u g = x
Assertion noinfdm ¬ x B y B ¬ y < s x dom T = z | p B z dom p q B ¬ p < s q p suc z = q suc z

Proof

Step Hyp Ref Expression
1 noinfdm.1 T = if x B y B ¬ y < s x ι x B | y B ¬ y < s x dom ι x B | y B ¬ y < s x 1 𝑜 g y | u B y dom u v B ¬ u < s v u suc y = v suc y ι x | u B g dom u v B ¬ u < s v u suc g = v suc g u g = x
2 iffalse ¬ x B y B ¬ y < s x if x B y B ¬ y < s x ι x B | y B ¬ y < s x dom ι x B | y B ¬ y < s x 1 𝑜 g y | u B y dom u v B ¬ u < s v u suc y = v suc y ι x | u B g dom u v B ¬ u < s v u suc g = v suc g u g = x = g y | u B y dom u v B ¬ u < s v u suc y = v suc y ι x | u B g dom u v B ¬ u < s v u suc g = v suc g u g = x
3 1 2 syl5eq ¬ x B y B ¬ y < s x T = g y | u B y dom u v B ¬ u < s v u suc y = v suc y ι x | u B g dom u v B ¬ u < s v u suc g = v suc g u g = x
4 3 dmeqd ¬ x B y B ¬ y < s x dom T = dom g y | u B y dom u v B ¬ u < s v u suc y = v suc y ι x | u B g dom u v B ¬ u < s v u suc g = v suc g u g = x
5 iotaex ι x | u B g dom u v B ¬ u < s v u suc g = v suc g u g = x V
6 eqid g y | u B y dom u v B ¬ u < s v u suc y = v suc y ι x | u B g dom u v B ¬ u < s v u suc g = v suc g u g = x = g y | u B y dom u v B ¬ u < s v u suc y = v suc y ι x | u B g dom u v B ¬ u < s v u suc g = v suc g u g = x
7 5 6 dmmpti dom g y | u B y dom u v B ¬ u < s v u suc y = v suc y ι x | u B g dom u v B ¬ u < s v u suc g = v suc g u g = x = y | u B y dom u v B ¬ u < s v u suc y = v suc y
8 eleq1w y = z y dom u z dom u
9 suceq y = z suc y = suc z
10 9 reseq2d y = z u suc y = u suc z
11 9 reseq2d y = z v suc y = v suc z
12 10 11 eqeq12d y = z u suc y = v suc y u suc z = v suc z
13 12 imbi2d y = z ¬ u < s v u suc y = v suc y ¬ u < s v u suc z = v suc z
14 13 ralbidv y = z v B ¬ u < s v u suc y = v suc y v B ¬ u < s v u suc z = v suc z
15 8 14 anbi12d y = z y dom u v B ¬ u < s v u suc y = v suc y z dom u v B ¬ u < s v u suc z = v suc z
16 15 rexbidv y = z u B y dom u v B ¬ u < s v u suc y = v suc y u B z dom u v B ¬ u < s v u suc z = v suc z
17 dmeq u = p dom u = dom p
18 17 eleq2d u = p z dom u z dom p
19 breq1 u = p u < s v p < s v
20 19 notbid u = p ¬ u < s v ¬ p < s v
21 reseq1 u = p u suc z = p suc z
22 21 eqeq1d u = p u suc z = v suc z p suc z = v suc z
23 20 22 imbi12d u = p ¬ u < s v u suc z = v suc z ¬ p < s v p suc z = v suc z
24 23 ralbidv u = p v B ¬ u < s v u suc z = v suc z v B ¬ p < s v p suc z = v suc z
25 breq2 v = q p < s v p < s q
26 25 notbid v = q ¬ p < s v ¬ p < s q
27 reseq1 v = q v suc z = q suc z
28 27 eqeq2d v = q p suc z = v suc z p suc z = q suc z
29 26 28 imbi12d v = q ¬ p < s v p suc z = v suc z ¬ p < s q p suc z = q suc z
30 29 cbvralvw v B ¬ p < s v p suc z = v suc z q B ¬ p < s q p suc z = q suc z
31 24 30 bitrdi u = p v B ¬ u < s v u suc z = v suc z q B ¬ p < s q p suc z = q suc z
32 18 31 anbi12d u = p z dom u v B ¬ u < s v u suc z = v suc z z dom p q B ¬ p < s q p suc z = q suc z
33 32 cbvrexvw u B z dom u v B ¬ u < s v u suc z = v suc z p B z dom p q B ¬ p < s q p suc z = q suc z
34 16 33 bitrdi y = z u B y dom u v B ¬ u < s v u suc y = v suc y p B z dom p q B ¬ p < s q p suc z = q suc z
35 34 cbvabv y | u B y dom u v B ¬ u < s v u suc y = v suc y = z | p B z dom p q B ¬ p < s q p suc z = q suc z
36 7 35 eqtri dom g y | u B y dom u v B ¬ u < s v u suc y = v suc y ι x | u B g dom u v B ¬ u < s v u suc g = v suc g u g = x = z | p B z dom p q B ¬ p < s q p suc z = q suc z
37 4 36 eqtrdi ¬ x B y B ¬ y < s x dom T = z | p B z dom p q B ¬ p < s q p suc z = q suc z