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Description: The upper bound of a closed interval is a member of it. (Contributed by Paul Chapman, 26-Nov-2007) (Revised by FL, 29-May-2014)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | ubicc2 | |- ( ( A e. RR* /\ B e. RR* /\ A <_ B ) -> B e. ( A [,] B ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | simp2 | |- ( ( A e. RR* /\ B e. RR* /\ A <_ B ) -> B e. RR* ) |
|
| 2 | simp3 | |- ( ( A e. RR* /\ B e. RR* /\ A <_ B ) -> A <_ B ) |
|
| 3 | xrleid | |- ( B e. RR* -> B <_ B ) |
|
| 4 | 3 | 3ad2ant2 | |- ( ( A e. RR* /\ B e. RR* /\ A <_ B ) -> B <_ B ) |
| 5 | elicc1 | |- ( ( A e. RR* /\ B e. RR* ) -> ( B e. ( A [,] B ) <-> ( B e. RR* /\ A <_ B /\ B <_ B ) ) ) |
|
| 6 | 5 | 3adant3 | |- ( ( A e. RR* /\ B e. RR* /\ A <_ B ) -> ( B e. ( A [,] B ) <-> ( B e. RR* /\ A <_ B /\ B <_ B ) ) ) |
| 7 | 1 2 4 6 | mpbir3and | |- ( ( A e. RR* /\ B e. RR* /\ A <_ B ) -> B e. ( A [,] B ) ) |