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Mirrors > Home > NFE Home > Th. List > sblbis | Unicode version |
Description: Introduce left biconditional inside of a substitution. (Contributed by NM, 19-Aug-1993.) |
Ref | Expression |
---|---|
sblbis.1 |
Ref | Expression |
---|---|
sblbis |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | sbbi 2071 | . 2 | |
2 | sblbis.1 | . . 3 | |
3 | 2 | bibi2i 304 | . 2 |
4 | 1, 3 | bitri 240 | 1 |
Colors of variables: wff setvar class |
Syntax hints: wb 176 wsb 1648 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1546 ax-5 1557 ax-17 1616 ax-9 1654 ax-8 1675 ax-6 1729 ax-7 1734 ax-11 1746 ax-12 1925 |
This theorem depends on definitions: df-bi 177 df-an 360 df-tru 1319 df-ex 1542 df-nf 1545 df-sb 1649 |
This theorem is referenced by: sb8eu 2222 sb8iota 4346 |
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