Description: Addition of a positive number increases the sum. (Contributed by Scott Fenton, 15-Apr-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | sltaddpos.1 | |- ( ph -> A e. No ) | |
| sltaddpos.2 | |- ( ph -> B e. No ) | ||
| Assertion | sltaddpos2d | |- ( ph -> ( 0s | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | sltaddpos.1 | |- ( ph -> A e. No ) | |
| 2 | sltaddpos.2 | |- ( ph -> B e. No ) | |
| 3 | 0sno | |- 0s e. No | |
| 4 | 3 | a1i | |- ( ph -> 0s e. No ) | 
| 5 | 4 1 2 | sltadd1d | |- ( ph -> ( 0s | 
| 6 | addslid | |- ( B e. No -> ( 0s +s B ) = B ) | |
| 7 | 2 6 | syl | |- ( ph -> ( 0s +s B ) = B ) | 
| 8 | 7 | breq1d | |- ( ph -> ( ( 0s +s B ) | 
| 9 | 5 8 | bitrd | |- ( ph -> ( 0s |