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Mirrors > Home > ILE Home > Th. List > biorfi | Unicode version |
Description: A wff is equivalent to its disjunction with falsehood. (Contributed by NM, 23-Mar-1995.) |
Ref | Expression |
---|---|
biorfi.1 |
Ref | Expression |
---|---|
biorfi |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | biorfi.1 | . 2 | |
2 | orc 665 | . . 3 | |
3 | orel2 677 | . . 3 | |
4 | 2, 3 | impbid2 141 | . 2 |
5 | 1, 4 | ax-mp 7 | 1 |
Colors of variables: wff set class |
Syntax hints: wn 3 wb 103 wo 661 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 104 ax-ia2 105 ax-ia3 106 ax-in2 577 ax-io 662 |
This theorem depends on definitions: df-bi 115 |
This theorem is referenced by: pm4.43 890 dn1dc 901 excxor 1309 un0 3278 opthprc 4409 frec0g 6006 dcdc 10572 |
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