Description: A nonnegative number plus one is a positive number. (Contributed by Mario Carneiro, 28-May-2016)
Ref | Expression | ||
---|---|---|---|
Hypotheses | rpgecld.1 | |- ( ph -> A e. RR ) |
|
ge0p1rp.2 | |- ( ph -> 0 <_ A ) |
||
Assertion | ge0p1rpd | |- ( ph -> ( A + 1 ) e. RR+ ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | rpgecld.1 | |- ( ph -> A e. RR ) |
|
2 | ge0p1rp.2 | |- ( ph -> 0 <_ A ) |
|
3 | ge0p1rp | |- ( ( A e. RR /\ 0 <_ A ) -> ( A + 1 ) e. RR+ ) |
|
4 | 1 2 3 | syl2anc | |- ( ph -> ( A + 1 ) e. RR+ ) |