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Description: The value of the structure replacement function (without the empty set) is a function if the structure (without the empty set) is a function. (Contributed by AV, 7-Jun-2021) (Revised by AV, 16-Nov-2021)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | setsn0fun.s | |- ( ph -> S Struct X ) |
|
| setsn0fun.i | |- ( ph -> I e. U ) |
||
| setsn0fun.e | |- ( ph -> E e. W ) |
||
| Assertion | setsn0fun | |- ( ph -> Fun ( ( S sSet <. I , E >. ) \ { (/) } ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | setsn0fun.s | |- ( ph -> S Struct X ) |
|
| 2 | setsn0fun.i | |- ( ph -> I e. U ) |
|
| 3 | setsn0fun.e | |- ( ph -> E e. W ) |
|
| 4 | structn0fun | |- ( S Struct X -> Fun ( S \ { (/) } ) ) |
|
| 5 | structex | |- ( S Struct X -> S e. _V ) |
|
| 6 | setsfun0 | |- ( ( ( S e. _V /\ Fun ( S \ { (/) } ) ) /\ ( I e. U /\ E e. W ) ) -> Fun ( ( S sSet <. I , E >. ) \ { (/) } ) ) |
|
| 7 | 5 6 | sylanl1 | |- ( ( ( S Struct X /\ Fun ( S \ { (/) } ) ) /\ ( I e. U /\ E e. W ) ) -> Fun ( ( S sSet <. I , E >. ) \ { (/) } ) ) |
| 8 | 7 | expcom | |- ( ( I e. U /\ E e. W ) -> ( ( S Struct X /\ Fun ( S \ { (/) } ) ) -> Fun ( ( S sSet <. I , E >. ) \ { (/) } ) ) ) |
| 9 | 2 3 8 | syl2anc | |- ( ph -> ( ( S Struct X /\ Fun ( S \ { (/) } ) ) -> Fun ( ( S sSet <. I , E >. ) \ { (/) } ) ) ) |
| 10 | 9 | com12 | |- ( ( S Struct X /\ Fun ( S \ { (/) } ) ) -> ( ph -> Fun ( ( S sSet <. I , E >. ) \ { (/) } ) ) ) |
| 11 | 4 10 | mpdan | |- ( S Struct X -> ( ph -> Fun ( ( S sSet <. I , E >. ) \ { (/) } ) ) ) |
| 12 | 1 11 | mpcom | |- ( ph -> Fun ( ( S sSet <. I , E >. ) \ { (/) } ) ) |