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Description: Composition in the trivial category. (Contributed by Zhi Wang, 22-Oct-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | funcsetc1o.1 | |- .1. = ( SetCat ` 1o ) |
|
| Assertion | setc1ocofval | |- { <. <. (/) , (/) >. , (/) , { <. (/) , (/) , (/) >. } >. } = ( comp ` .1. ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | funcsetc1o.1 | |- .1. = ( SetCat ` 1o ) |
|
| 2 | df-ot | |- <. <. (/) , (/) >. , (/) , { <. (/) , (/) , (/) >. } >. = <. <. <. (/) , (/) >. , (/) >. , { <. (/) , (/) , (/) >. } >. |
|
| 3 | 2 | sneqi | |- { <. <. (/) , (/) >. , (/) , { <. (/) , (/) , (/) >. } >. } = { <. <. <. (/) , (/) >. , (/) >. , { <. (/) , (/) , (/) >. } >. } |
| 4 | opex | |- <. (/) , (/) >. e. _V |
|
| 5 | 0ex | |- (/) e. _V |
|
| 6 | snex | |- { <. (/) , (/) , (/) >. } e. _V |
|
| 7 | df1o2 | |- 1o = { (/) } |
|
| 8 | 7 | fveq2i | |- ( SetCat ` 1o ) = ( SetCat ` { (/) } ) |
| 9 | 1 8 | eqtri | |- .1. = ( SetCat ` { (/) } ) |
| 10 | snex | |- { (/) } e. _V |
|
| 11 | 10 | a1i | |- ( T. -> { (/) } e. _V ) |
| 12 | eqid | |- ( comp ` .1. ) = ( comp ` .1. ) |
|
| 13 | 9 11 12 | setccofval | |- ( T. -> ( comp ` .1. ) = ( v e. ( { (/) } X. { (/) } ) , z e. { (/) } |-> ( g e. ( z ^m ( 2nd ` v ) ) , f e. ( ( 2nd ` v ) ^m ( 1st ` v ) ) |-> ( g o. f ) ) ) ) |
| 14 | 13 | mptru | |- ( comp ` .1. ) = ( v e. ( { (/) } X. { (/) } ) , z e. { (/) } |-> ( g e. ( z ^m ( 2nd ` v ) ) , f e. ( ( 2nd ` v ) ^m ( 1st ` v ) ) |-> ( g o. f ) ) ) |
| 15 | 5 5 | xpsn | |- ( { (/) } X. { (/) } ) = { <. (/) , (/) >. } |
| 16 | eqid | |- { (/) } = { (/) } |
|
| 17 | eqid | |- ( g e. ( z ^m ( 2nd ` v ) ) , f e. ( ( 2nd ` v ) ^m ( 1st ` v ) ) |-> ( g o. f ) ) = ( g e. ( z ^m ( 2nd ` v ) ) , f e. ( ( 2nd ` v ) ^m ( 1st ` v ) ) |-> ( g o. f ) ) |
|
| 18 | 15 16 17 | mpoeq123i | |- ( v e. ( { (/) } X. { (/) } ) , z e. { (/) } |-> ( g e. ( z ^m ( 2nd ` v ) ) , f e. ( ( 2nd ` v ) ^m ( 1st ` v ) ) |-> ( g o. f ) ) ) = ( v e. { <. (/) , (/) >. } , z e. { (/) } |-> ( g e. ( z ^m ( 2nd ` v ) ) , f e. ( ( 2nd ` v ) ^m ( 1st ` v ) ) |-> ( g o. f ) ) ) |
| 19 | 14 18 | eqtri | |- ( comp ` .1. ) = ( v e. { <. (/) , (/) >. } , z e. { (/) } |-> ( g e. ( z ^m ( 2nd ` v ) ) , f e. ( ( 2nd ` v ) ^m ( 1st ` v ) ) |-> ( g o. f ) ) ) |
| 20 | 5 5 | op2ndd | |- ( v = <. (/) , (/) >. -> ( 2nd ` v ) = (/) ) |
| 21 | 20 | oveq2d | |- ( v = <. (/) , (/) >. -> ( z ^m ( 2nd ` v ) ) = ( z ^m (/) ) ) |
| 22 | 5 5 | op1std | |- ( v = <. (/) , (/) >. -> ( 1st ` v ) = (/) ) |
| 23 | 20 22 | oveq12d | |- ( v = <. (/) , (/) >. -> ( ( 2nd ` v ) ^m ( 1st ` v ) ) = ( (/) ^m (/) ) ) |
| 24 | 0map0sn0 | |- ( (/) ^m (/) ) = { (/) } |
|
| 25 | 23 24 | eqtrdi | |- ( v = <. (/) , (/) >. -> ( ( 2nd ` v ) ^m ( 1st ` v ) ) = { (/) } ) |
| 26 | eqidd | |- ( v = <. (/) , (/) >. -> ( g o. f ) = ( g o. f ) ) |
|
| 27 | 21 25 26 | mpoeq123dv | |- ( v = <. (/) , (/) >. -> ( g e. ( z ^m ( 2nd ` v ) ) , f e. ( ( 2nd ` v ) ^m ( 1st ` v ) ) |-> ( g o. f ) ) = ( g e. ( z ^m (/) ) , f e. { (/) } |-> ( g o. f ) ) ) |
| 28 | oveq1 | |- ( z = (/) -> ( z ^m (/) ) = ( (/) ^m (/) ) ) |
|
| 29 | 28 24 | eqtrdi | |- ( z = (/) -> ( z ^m (/) ) = { (/) } ) |
| 30 | eqidd | |- ( z = (/) -> { (/) } = { (/) } ) |
|
| 31 | eqidd | |- ( z = (/) -> ( g o. f ) = ( g o. f ) ) |
|
| 32 | 29 30 31 | mpoeq123dv | |- ( z = (/) -> ( g e. ( z ^m (/) ) , f e. { (/) } |-> ( g o. f ) ) = ( g e. { (/) } , f e. { (/) } |-> ( g o. f ) ) ) |
| 33 | eqid | |- ( g e. { (/) } , f e. { (/) } |-> ( g o. f ) ) = ( g e. { (/) } , f e. { (/) } |-> ( g o. f ) ) |
|
| 34 | coeq1 | |- ( g = (/) -> ( g o. f ) = ( (/) o. f ) ) |
|
| 35 | co01 | |- ( (/) o. f ) = (/) |
|
| 36 | 34 35 | eqtrdi | |- ( g = (/) -> ( g o. f ) = (/) ) |
| 37 | eqidd | |- ( f = (/) -> (/) = (/) ) |
|
| 38 | 33 36 37 | mposn | |- ( ( (/) e. _V /\ (/) e. _V /\ (/) e. _V ) -> ( g e. { (/) } , f e. { (/) } |-> ( g o. f ) ) = { <. <. (/) , (/) >. , (/) >. } ) |
| 39 | 5 5 5 38 | mp3an | |- ( g e. { (/) } , f e. { (/) } |-> ( g o. f ) ) = { <. <. (/) , (/) >. , (/) >. } |
| 40 | 32 39 | eqtrdi | |- ( z = (/) -> ( g e. ( z ^m (/) ) , f e. { (/) } |-> ( g o. f ) ) = { <. <. (/) , (/) >. , (/) >. } ) |
| 41 | df-ot | |- <. (/) , (/) , (/) >. = <. <. (/) , (/) >. , (/) >. |
|
| 42 | 41 | sneqi | |- { <. (/) , (/) , (/) >. } = { <. <. (/) , (/) >. , (/) >. } |
| 43 | 40 42 | eqtr4di | |- ( z = (/) -> ( g e. ( z ^m (/) ) , f e. { (/) } |-> ( g o. f ) ) = { <. (/) , (/) , (/) >. } ) |
| 44 | 19 27 43 | mposn | |- ( ( <. (/) , (/) >. e. _V /\ (/) e. _V /\ { <. (/) , (/) , (/) >. } e. _V ) -> ( comp ` .1. ) = { <. <. <. (/) , (/) >. , (/) >. , { <. (/) , (/) , (/) >. } >. } ) |
| 45 | 4 5 6 44 | mp3an | |- ( comp ` .1. ) = { <. <. <. (/) , (/) >. , (/) >. , { <. (/) , (/) , (/) >. } >. } |
| 46 | 3 45 | eqtr4i | |- { <. <. (/) , (/) >. , (/) , { <. (/) , (/) , (/) >. } >. } = ( comp ` .1. ) |