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Mirrors > Home > MPE Home > Th. List > ord0 | Structured version Visualization version Unicode version |
Description: The empty set is an ordinal class. (Contributed by NM, 11-May-1994.) |
Ref | Expression |
---|---|
ord0 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | tr0 4764 | . 2 | |
2 | we0 5109 | . 2 | |
3 | df-ord 5726 | . 2 | |
4 | 1, 2, 3 | mpbir2an 955 | 1 |
Colors of variables: wff setvar class |
Syntax hints: c0 3915 wtr 4752 cep 5028 wwe 5072 word 5722 |
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 |
This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 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-ne 2795 df-ral 2917 df-rex 2918 df-rab 2921 df-v 3202 df-dif 3577 df-in 3581 df-ss 3588 df-nul 3916 df-pw 4160 df-uni 4437 df-tr 4753 df-po 5035 df-so 5036 df-fr 5073 df-we 5075 df-ord 5726 |
This theorem is referenced by: 0elon 5778 ord0eln0 5779 ordzsl 7045 smo0 7455 oicl 8434 alephgeom 8905 |
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