Theorem csbcow 3068

Description: Composition law for chained substitutions into a class. Version of csbco 3067 with a disjoint variable condition, which requires fewer axioms. (Contributed by NM, 10-Nov-2005.) (Revised by Gino Giotto, 25-Aug-2024.)

Assertion

Ref	Expression
csbcow	⊢ ⦋𝐴 / 𝑦⦌⦋𝑦 / 𝑥⦌𝐵 = ⦋𝐴 / 𝑥⦌𝐵

Distinct variable groups:   𝑥,𝑦   𝑦,𝐵

Allowed substitution hints:   𝐴(𝑥,𝑦)   𝐵(𝑥)

Proof of Theorem csbcow

Dummy variables 𝑧 𝑤 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		df-csb 3058	. . . . . 6 ⊢ ⦋𝑦 / 𝑥⦌𝐵 = {𝑧 ∣ [𝑦 / 𝑥]𝑧 ∈ 𝐵}
2	1	abeq2i 2288	. . . . 5 ⊢ (𝑧 ∈ ⦋𝑦 / 𝑥⦌𝐵 ↔ [𝑦 / 𝑥]𝑧 ∈ 𝐵)
3	2	sbcbii 3022	. . . 4 ⊢ ([𝐴 / 𝑦]𝑧 ∈ ⦋𝑦 / 𝑥⦌𝐵 ↔ [𝐴 / 𝑦][𝑦 / 𝑥]𝑧 ∈ 𝐵)
4		nfv 1528	. . . . . . . . . 10 ⊢ Ⅎ𝑦∀𝑥(𝑥 = 𝑤 → 𝑧 ∈ 𝐵)
5		equequ2 1713	. . . . . . . . . . . 12 ⊢ (𝑦 = 𝑤 → (𝑥 = 𝑦 ↔ 𝑥 = 𝑤))
6	5	imbi1d 231	. . . . . . . . . . 11 ⊢ (𝑦 = 𝑤 → ((𝑥 = 𝑦 → 𝑧 ∈ 𝐵) ↔ (𝑥 = 𝑤 → 𝑧 ∈ 𝐵)))
7	6	albidv 1824	. . . . . . . . . 10 ⊢ (𝑦 = 𝑤 → (∀𝑥(𝑥 = 𝑦 → 𝑧 ∈ 𝐵) ↔ ∀𝑥(𝑥 = 𝑤 → 𝑧 ∈ 𝐵)))
8	4, 7	sbiev 1792	. . . . . . . . 9 ⊢ ([𝑤 / 𝑦]∀𝑥(𝑥 = 𝑦 → 𝑧 ∈ 𝐵) ↔ ∀𝑥(𝑥 = 𝑤 → 𝑧 ∈ 𝐵))
9		sb6 1886	. . . . . . . . 9 ⊢ ([𝑤 / 𝑥]𝑧 ∈ 𝐵 ↔ ∀𝑥(𝑥 = 𝑤 → 𝑧 ∈ 𝐵))
10	8, 9	bitr4i 187	. . . . . . . 8 ⊢ ([𝑤 / 𝑦]∀𝑥(𝑥 = 𝑦 → 𝑧 ∈ 𝐵) ↔ [𝑤 / 𝑥]𝑧 ∈ 𝐵)
11		df-clab 2164	. . . . . . . 8 ⊢ (𝑤 ∈ {𝑦 ∣ ∀𝑥(𝑥 = 𝑦 → 𝑧 ∈ 𝐵)} ↔ [𝑤 / 𝑦]∀𝑥(𝑥 = 𝑦 → 𝑧 ∈ 𝐵))
12		df-clab 2164	. . . . . . . 8 ⊢ (𝑤 ∈ {𝑥 ∣ 𝑧 ∈ 𝐵} ↔ [𝑤 / 𝑥]𝑧 ∈ 𝐵)
13	10, 11, 12	3bitr4i 212	. . . . . . 7 ⊢ (𝑤 ∈ {𝑦 ∣ ∀𝑥(𝑥 = 𝑦 → 𝑧 ∈ 𝐵)} ↔ 𝑤 ∈ {𝑥 ∣ 𝑧 ∈ 𝐵})
14	13	eqriv 2174	. . . . . 6 ⊢ {𝑦 ∣ ∀𝑥(𝑥 = 𝑦 → 𝑧 ∈ 𝐵)} = {𝑥 ∣ 𝑧 ∈ 𝐵}
15	14	eleq2i 2244	. . . . 5 ⊢ (𝐴 ∈ {𝑦 ∣ ∀𝑥(𝑥 = 𝑦 → 𝑧 ∈ 𝐵)} ↔ 𝐴 ∈ {𝑥 ∣ 𝑧 ∈ 𝐵})
16		df-sbc 2963	. . . . . 6 ⊢ ([𝐴 / 𝑦][𝑦 / 𝑥]𝑧 ∈ 𝐵 ↔ 𝐴 ∈ {𝑦 ∣ [𝑦 / 𝑥]𝑧 ∈ 𝐵})
17		df-sbc 2963	. . . . . . . . 9 ⊢ ([𝑦 / 𝑥]𝑧 ∈ 𝐵 ↔ 𝑦 ∈ {𝑥 ∣ 𝑧 ∈ 𝐵})
18		df-clab 2164	. . . . . . . . . 10 ⊢ (𝑦 ∈ {𝑥 ∣ 𝑧 ∈ 𝐵} ↔ [𝑦 / 𝑥]𝑧 ∈ 𝐵)
19		sb6 1886	. . . . . . . . . 10 ⊢ ([𝑦 / 𝑥]𝑧 ∈ 𝐵 ↔ ∀𝑥(𝑥 = 𝑦 → 𝑧 ∈ 𝐵))
20	18, 19	bitri 184	. . . . . . . . 9 ⊢ (𝑦 ∈ {𝑥 ∣ 𝑧 ∈ 𝐵} ↔ ∀𝑥(𝑥 = 𝑦 → 𝑧 ∈ 𝐵))
21	17, 20	bitri 184	. . . . . . . 8 ⊢ ([𝑦 / 𝑥]𝑧 ∈ 𝐵 ↔ ∀𝑥(𝑥 = 𝑦 → 𝑧 ∈ 𝐵))
22	21	abbii 2293	. . . . . . 7 ⊢ {𝑦 ∣ [𝑦 / 𝑥]𝑧 ∈ 𝐵} = {𝑦 ∣ ∀𝑥(𝑥 = 𝑦 → 𝑧 ∈ 𝐵)}
23	22	eleq2i 2244	. . . . . 6 ⊢ (𝐴 ∈ {𝑦 ∣ [𝑦 / 𝑥]𝑧 ∈ 𝐵} ↔ 𝐴 ∈ {𝑦 ∣ ∀𝑥(𝑥 = 𝑦 → 𝑧 ∈ 𝐵)})
24	16, 23	bitri 184	. . . . 5 ⊢ ([𝐴 / 𝑦][𝑦 / 𝑥]𝑧 ∈ 𝐵 ↔ 𝐴 ∈ {𝑦 ∣ ∀𝑥(𝑥 = 𝑦 → 𝑧 ∈ 𝐵)})
25		df-sbc 2963	. . . . 5 ⊢ ([𝐴 / 𝑥]𝑧 ∈ 𝐵 ↔ 𝐴 ∈ {𝑥 ∣ 𝑧 ∈ 𝐵})
26	15, 24, 25	3bitr4i 212	. . . 4 ⊢ ([𝐴 / 𝑦][𝑦 / 𝑥]𝑧 ∈ 𝐵 ↔ [𝐴 / 𝑥]𝑧 ∈ 𝐵)
27	3, 26	bitri 184	. . 3 ⊢ ([𝐴 / 𝑦]𝑧 ∈ ⦋𝑦 / 𝑥⦌𝐵 ↔ [𝐴 / 𝑥]𝑧 ∈ 𝐵)
28	27	abbii 2293	. 2 ⊢ {𝑧 ∣ [𝐴 / 𝑦]𝑧 ∈ ⦋𝑦 / 𝑥⦌𝐵} = {𝑧 ∣ [𝐴 / 𝑥]𝑧 ∈ 𝐵}
29		df-csb 3058	. 2 ⊢ ⦋𝐴 / 𝑦⦌⦋𝑦 / 𝑥⦌𝐵 = {𝑧 ∣ [𝐴 / 𝑦]𝑧 ∈ ⦋𝑦 / 𝑥⦌𝐵}
30		df-csb 3058	. 2 ⊢ ⦋𝐴 / 𝑥⦌𝐵 = {𝑧 ∣ [𝐴 / 𝑥]𝑧 ∈ 𝐵}
31	28, 29, 30	3eqtr4i 2208	1 ⊢ ⦋𝐴 / 𝑦⦌⦋𝑦 / 𝑥⦌𝐵 = ⦋𝐴 / 𝑥⦌𝐵

Syntax hints:   → wi 4  ∀wal 1351   = wceq 1353  [wsb 1762   ∈ wcel 2148  {cab 2163  [wsbc 2962  ⦋csb 3057

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-5 1447  ax-7 1448  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-8 1504  ax-11 1506  ax-4 1510  ax-17 1526  ax-i9 1530  ax-ial 1534  ax-i5r 1535  ax-ext 2159

This theorem depends on definitions:  df-bi 117  df-tru 1356  df-nf 1461  df-sb 1763  df-clab 2164  df-cleq 2170  df-clel 2173  df-sbc 2963  df-csb 3058

This theorem is referenced by:  zproddc  11582  fprodseq  11586