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Mirrors > Home > MPE Home > Th. List > ord3ex | Structured version Visualization version GIF version |
Description: The ordinal number 3 is a set, proved without the Axiom of Union ax-un 6949. (Contributed by NM, 2-May-2009.) |
Ref | Expression |
---|---|
ord3ex | ⊢ {∅, {∅}, {∅, {∅}}} ∈ V |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-tp 4182 | . 2 ⊢ {∅, {∅}, {∅, {∅}}} = ({∅, {∅}} ∪ {{∅, {∅}}}) | |
2 | pwpr 4430 | . . . 4 ⊢ 𝒫 {∅, {∅}} = ({∅, {∅}} ∪ {{{∅}}, {∅, {∅}}}) | |
3 | pp0ex 4855 | . . . . 5 ⊢ {∅, {∅}} ∈ V | |
4 | 3 | pwex 4848 | . . . 4 ⊢ 𝒫 {∅, {∅}} ∈ V |
5 | 2, 4 | eqeltrri 2698 | . . 3 ⊢ ({∅, {∅}} ∪ {{{∅}}, {∅, {∅}}}) ∈ V |
6 | snsspr2 4346 | . . . 4 ⊢ {{∅, {∅}}} ⊆ {{{∅}}, {∅, {∅}}} | |
7 | unss2 3784 | . . . 4 ⊢ ({{∅, {∅}}} ⊆ {{{∅}}, {∅, {∅}}} → ({∅, {∅}} ∪ {{∅, {∅}}}) ⊆ ({∅, {∅}} ∪ {{{∅}}, {∅, {∅}}})) | |
8 | 6, 7 | ax-mp 5 | . . 3 ⊢ ({∅, {∅}} ∪ {{∅, {∅}}}) ⊆ ({∅, {∅}} ∪ {{{∅}}, {∅, {∅}}}) |
9 | 5, 8 | ssexi 4803 | . 2 ⊢ ({∅, {∅}} ∪ {{∅, {∅}}}) ∈ V |
10 | 1, 9 | eqeltri 2697 | 1 ⊢ {∅, {∅}, {∅, {∅}}} ∈ V |
Colors of variables: wff setvar class |
Syntax hints: ∈ wcel 1990 Vcvv 3200 ∪ cun 3572 ⊆ wss 3574 ∅c0 3915 𝒫 cpw 4158 {csn 4177 {cpr 4179 {ctp 4181 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1722 ax-4 1737 ax-5 1839 ax-6 1888 ax-7 1935 ax-9 1999 ax-10 2019 ax-11 2034 ax-12 2047 ax-13 2246 ax-ext 2602 ax-sep 4781 ax-nul 4789 ax-pow 4843 |
This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 df-3an 1039 df-tru 1486 df-ex 1705 df-nf 1710 df-sb 1881 df-clab 2609 df-cleq 2615 df-clel 2618 df-nfc 2753 df-ral 2917 df-v 3202 df-dif 3577 df-un 3579 df-in 3581 df-ss 3588 df-nul 3916 df-pw 4160 df-sn 4178 df-pr 4180 df-tp 4182 |
This theorem is referenced by: (None) |
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