Description: The generalized sum of nonnegative extended reals is not minus infinity. (Contributed by Glauco Siliprandi, 11-Oct-2020)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | sge0nemnf.1 | |- ( ph -> A e. V ) | |
| sge0nemnf.2 | |- ( ph -> F : A --> ( 0 [,] +oo ) ) | ||
| Assertion | sge0nemnf | |- ( ph -> ( sum^ ` F ) =/= -oo ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | sge0nemnf.1 | |- ( ph -> A e. V ) | |
| 2 | sge0nemnf.2 | |- ( ph -> F : A --> ( 0 [,] +oo ) ) | |
| 3 | 1 2 | sge0cl | |- ( ph -> ( sum^ ` F ) e. ( 0 [,] +oo ) ) | 
| 4 | xrge0neqmnf | |- ( ( sum^ ` F ) e. ( 0 [,] +oo ) -> ( sum^ ` F ) =/= -oo ) | |
| 5 | 3 4 | syl | |- ( ph -> ( sum^ ` F ) =/= -oo ) |