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Mirrors > Home > NFE Home > Th. List > mtord | Unicode version |
Description: A modus tollens deduction involving disjunction. (Contributed by Jeff Hankins, 15-Jul-2009.) |
Ref | Expression |
---|---|
mtord.1 |
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mtord.2 |
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mtord.3 |
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Ref | Expression |
---|---|
mtord |
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Step | Hyp | Ref | Expression |
---|---|---|---|
1 | mtord.2 |
. 2
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2 | mtord.1 |
. . 3
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3 | mtord.3 |
. . . 4
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4 | df-or 359 |
. . . 4
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5 | 3, 4 | syl6ib 217 |
. . 3
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6 | 2, 5 | mpid 37 |
. 2
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7 | 1, 6 | mtod 168 |
1
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Colors of variables: wff setvar class |
Syntax hints: ![]() ![]() ![]() |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 |
This theorem depends on definitions: df-bi 177 df-or 359 |
This theorem is referenced by: (None) |
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