![]() |
Metamath Proof Explorer |
< Previous
Next >
Nearby theorems |
|
Mirrors > Home > MPE Home > Th. List > dfdm3 | Structured version Visualization version GIF version |
Description: Alternate definition of domain. Definition 6.5(1) of [TakeutiZaring] p. 24. (Contributed by NM, 28-Dec-1996.) |
Ref | Expression |
---|---|
dfdm3 | ⊢ dom 𝐴 = {𝑥 ∣ ∃𝑦⟨𝑥, 𝑦⟩ ∈ 𝐴} |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-dm 5644 | . 2 ⊢ dom 𝐴 = {𝑥 ∣ ∃𝑦 𝑥𝐴𝑦} | |
2 | df-br 5107 | . . . 4 ⊢ (𝑥𝐴𝑦 ↔ ⟨𝑥, 𝑦⟩ ∈ 𝐴) | |
3 | 2 | exbii 1851 | . . 3 ⊢ (∃𝑦 𝑥𝐴𝑦 ↔ ∃𝑦⟨𝑥, 𝑦⟩ ∈ 𝐴) |
4 | 3 | abbii 2803 | . 2 ⊢ {𝑥 ∣ ∃𝑦 𝑥𝐴𝑦} = {𝑥 ∣ ∃𝑦⟨𝑥, 𝑦⟩ ∈ 𝐴} |
5 | 1, 4 | eqtri 2761 | 1 ⊢ dom 𝐴 = {𝑥 ∣ ∃𝑦⟨𝑥, 𝑦⟩ ∈ 𝐴} |
Colors of variables: wff setvar class |
Syntax hints: = wceq 1542 ∃wex 1782 ∈ wcel 2107 {cab 2710 ⟨cop 4593 class class class wbr 5106 dom cdm 5634 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1798 ax-4 1812 ax-5 1914 ax-6 1972 ax-7 2012 ax-9 2117 ax-ext 2704 |
This theorem depends on definitions: df-bi 206 df-an 398 df-ex 1783 df-sb 2069 df-clab 2711 df-cleq 2725 df-br 5107 df-dm 5644 |
This theorem is referenced by: csbdm 5854 cnextf 23433 dmrab 31468 |
Copyright terms: Public domain | W3C validator |