Description: A mixed syllogism inference from a nested implication and a biconditional. Useful for substituting an embedded consequent with a definition. (Contributed by NM, 5-Aug-1993)
Ref | Expression | ||
---|---|---|---|
Hypotheses | imbitrrdi.1 | |
|
imbitrrdi.2 | |
||
Assertion | imbitrrdi | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | imbitrrdi.1 | |
|
2 | imbitrrdi.2 | |
|
3 | 2 | biimpri | |
4 | 1 3 | syl6 | |