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Description: A nonnegative number plus one is a positive number. (Contributed by Mario Carneiro, 5-Oct-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | ge0p1rp | |- ( ( A e. RR /\ 0 <_ A ) -> ( A + 1 ) e. RR+ ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | peano2re | |- ( A e. RR -> ( A + 1 ) e. RR ) |
|
| 2 | 1 | adantr | |- ( ( A e. RR /\ 0 <_ A ) -> ( A + 1 ) e. RR ) |
| 3 | 0red | |- ( ( A e. RR /\ 0 <_ A ) -> 0 e. RR ) |
|
| 4 | simpl | |- ( ( A e. RR /\ 0 <_ A ) -> A e. RR ) |
|
| 5 | simpr | |- ( ( A e. RR /\ 0 <_ A ) -> 0 <_ A ) |
|
| 6 | ltp1 | |- ( A e. RR -> A < ( A + 1 ) ) |
|
| 7 | 6 | adantr | |- ( ( A e. RR /\ 0 <_ A ) -> A < ( A + 1 ) ) |
| 8 | 3 4 2 5 7 | lelttrd | |- ( ( A e. RR /\ 0 <_ A ) -> 0 < ( A + 1 ) ) |
| 9 | elrp | |- ( ( A + 1 ) e. RR+ <-> ( ( A + 1 ) e. RR /\ 0 < ( A + 1 ) ) ) |
|
| 10 | 2 8 9 | sylanbrc | |- ( ( A e. RR /\ 0 <_ A ) -> ( A + 1 ) e. RR+ ) |