| Step | Hyp | Ref | Expression | 
						
							| 1 |  | nzerooringczr.u |  |-  ( ph -> U e. V ) | 
						
							| 2 |  | nzerooringczr.c |  |-  C = ( RingCat ` U ) | 
						
							| 3 |  | nzerooringczr.z |  |-  ( ph -> Z e. ( Ring \ NzRing ) ) | 
						
							| 4 |  | nzerooringczr.e |  |-  ( ph -> Z e. U ) | 
						
							| 5 |  | nzerooringczr.i |  |-  ( ph -> ZZring e. U ) | 
						
							| 6 |  | ax-1 |  |-  ( ( ZeroO ` C ) = (/) -> ( ph -> ( ZeroO ` C ) = (/) ) ) | 
						
							| 7 |  | neq0 |  |-  ( -. ( ZeroO ` C ) = (/) <-> E. h h e. ( ZeroO ` C ) ) | 
						
							| 8 | 2 | ringccat |  |-  ( U e. V -> C e. Cat ) | 
						
							| 9 | 1 8 | syl |  |-  ( ph -> C e. Cat ) | 
						
							| 10 |  | iszeroi |  |-  ( ( C e. Cat /\ h e. ( ZeroO ` C ) ) -> ( h e. ( Base ` C ) /\ ( h e. ( InitO ` C ) /\ h e. ( TermO ` C ) ) ) ) | 
						
							| 11 | 9 10 | sylan |  |-  ( ( ph /\ h e. ( ZeroO ` C ) ) -> ( h e. ( Base ` C ) /\ ( h e. ( InitO ` C ) /\ h e. ( TermO ` C ) ) ) ) | 
						
							| 12 | 1 2 3 4 | zrtermoringc |  |-  ( ph -> Z e. ( TermO ` C ) ) | 
						
							| 13 | 1 5 2 | irinitoringc |  |-  ( ph -> ZZring e. ( InitO ` C ) ) | 
						
							| 14 | 9 | ad2antrr |  |-  ( ( ( ph /\ h e. ( InitO ` C ) ) /\ ZZring e. ( InitO ` C ) ) -> C e. Cat ) | 
						
							| 15 |  | simplr |  |-  ( ( ( ph /\ h e. ( InitO ` C ) ) /\ ZZring e. ( InitO ` C ) ) -> h e. ( InitO ` C ) ) | 
						
							| 16 |  | simpr |  |-  ( ( ( ph /\ h e. ( InitO ` C ) ) /\ ZZring e. ( InitO ` C ) ) -> ZZring e. ( InitO ` C ) ) | 
						
							| 17 | 14 15 16 | initoeu1w |  |-  ( ( ( ph /\ h e. ( InitO ` C ) ) /\ ZZring e. ( InitO ` C ) ) -> h ( ~=c ` C ) ZZring ) | 
						
							| 18 | 9 | ad2antrr |  |-  ( ( ( ph /\ h e. ( TermO ` C ) ) /\ Z e. ( TermO ` C ) ) -> C e. Cat ) | 
						
							| 19 |  | simpr |  |-  ( ( ( ph /\ h e. ( TermO ` C ) ) /\ Z e. ( TermO ` C ) ) -> Z e. ( TermO ` C ) ) | 
						
							| 20 |  | simplr |  |-  ( ( ( ph /\ h e. ( TermO ` C ) ) /\ Z e. ( TermO ` C ) ) -> h e. ( TermO ` C ) ) | 
						
							| 21 | 18 19 20 | termoeu1w |  |-  ( ( ( ph /\ h e. ( TermO ` C ) ) /\ Z e. ( TermO ` C ) ) -> Z ( ~=c ` C ) h ) | 
						
							| 22 |  | cictr |  |-  ( ( C e. Cat /\ Z ( ~=c ` C ) h /\ h ( ~=c ` C ) ZZring ) -> Z ( ~=c ` C ) ZZring ) | 
						
							| 23 | 9 22 | syl3an1 |  |-  ( ( ph /\ Z ( ~=c ` C ) h /\ h ( ~=c ` C ) ZZring ) -> Z ( ~=c ` C ) ZZring ) | 
						
							| 24 |  | eqid |  |-  ( Iso ` C ) = ( Iso ` C ) | 
						
							| 25 |  | eqid |  |-  ( Base ` C ) = ( Base ` C ) | 
						
							| 26 | 3 | eldifad |  |-  ( ph -> Z e. Ring ) | 
						
							| 27 | 4 26 | elind |  |-  ( ph -> Z e. ( U i^i Ring ) ) | 
						
							| 28 | 2 25 1 | ringcbas |  |-  ( ph -> ( Base ` C ) = ( U i^i Ring ) ) | 
						
							| 29 | 27 28 | eleqtrrd |  |-  ( ph -> Z e. ( Base ` C ) ) | 
						
							| 30 |  | zringring |  |-  ZZring e. Ring | 
						
							| 31 | 30 | a1i |  |-  ( ph -> ZZring e. Ring ) | 
						
							| 32 | 5 31 | elind |  |-  ( ph -> ZZring e. ( U i^i Ring ) ) | 
						
							| 33 | 32 28 | eleqtrrd |  |-  ( ph -> ZZring e. ( Base ` C ) ) | 
						
							| 34 | 24 25 9 29 33 | cic |  |-  ( ph -> ( Z ( ~=c ` C ) ZZring <-> E. f f e. ( Z ( Iso ` C ) ZZring ) ) ) | 
						
							| 35 |  | n0 |  |-  ( ( Z ( Iso ` C ) ZZring ) =/= (/) <-> E. f f e. ( Z ( Iso ` C ) ZZring ) ) | 
						
							| 36 |  | eqid |  |-  ( Hom ` C ) = ( Hom ` C ) | 
						
							| 37 | 25 36 24 9 29 33 | isohom |  |-  ( ph -> ( Z ( Iso ` C ) ZZring ) C_ ( Z ( Hom ` C ) ZZring ) ) | 
						
							| 38 |  | ssn0 |  |-  ( ( ( Z ( Iso ` C ) ZZring ) C_ ( Z ( Hom ` C ) ZZring ) /\ ( Z ( Iso ` C ) ZZring ) =/= (/) ) -> ( Z ( Hom ` C ) ZZring ) =/= (/) ) | 
						
							| 39 | 2 25 1 36 29 33 | ringchom |  |-  ( ph -> ( Z ( Hom ` C ) ZZring ) = ( Z RingHom ZZring ) ) | 
						
							| 40 | 39 | neeq1d |  |-  ( ph -> ( ( Z ( Hom ` C ) ZZring ) =/= (/) <-> ( Z RingHom ZZring ) =/= (/) ) ) | 
						
							| 41 |  | zringnzr |  |-  ZZring e. NzRing | 
						
							| 42 |  | nrhmzr |  |-  ( ( Z e. ( Ring \ NzRing ) /\ ZZring e. NzRing ) -> ( Z RingHom ZZring ) = (/) ) | 
						
							| 43 | 3 41 42 | sylancl |  |-  ( ph -> ( Z RingHom ZZring ) = (/) ) | 
						
							| 44 |  | eqneqall |  |-  ( ( Z RingHom ZZring ) = (/) -> ( ( Z RingHom ZZring ) =/= (/) -> ( ZeroO ` C ) = (/) ) ) | 
						
							| 45 | 43 44 | syl |  |-  ( ph -> ( ( Z RingHom ZZring ) =/= (/) -> ( ZeroO ` C ) = (/) ) ) | 
						
							| 46 | 40 45 | sylbid |  |-  ( ph -> ( ( Z ( Hom ` C ) ZZring ) =/= (/) -> ( ZeroO ` C ) = (/) ) ) | 
						
							| 47 | 38 46 | syl5com |  |-  ( ( ( Z ( Iso ` C ) ZZring ) C_ ( Z ( Hom ` C ) ZZring ) /\ ( Z ( Iso ` C ) ZZring ) =/= (/) ) -> ( ph -> ( ZeroO ` C ) = (/) ) ) | 
						
							| 48 | 47 | expcom |  |-  ( ( Z ( Iso ` C ) ZZring ) =/= (/) -> ( ( Z ( Iso ` C ) ZZring ) C_ ( Z ( Hom ` C ) ZZring ) -> ( ph -> ( ZeroO ` C ) = (/) ) ) ) | 
						
							| 49 | 48 | com13 |  |-  ( ph -> ( ( Z ( Iso ` C ) ZZring ) C_ ( Z ( Hom ` C ) ZZring ) -> ( ( Z ( Iso ` C ) ZZring ) =/= (/) -> ( ZeroO ` C ) = (/) ) ) ) | 
						
							| 50 | 37 49 | mpd |  |-  ( ph -> ( ( Z ( Iso ` C ) ZZring ) =/= (/) -> ( ZeroO ` C ) = (/) ) ) | 
						
							| 51 | 35 50 | biimtrrid |  |-  ( ph -> ( E. f f e. ( Z ( Iso ` C ) ZZring ) -> ( ZeroO ` C ) = (/) ) ) | 
						
							| 52 | 34 51 | sylbid |  |-  ( ph -> ( Z ( ~=c ` C ) ZZring -> ( ZeroO ` C ) = (/) ) ) | 
						
							| 53 | 52 | 3ad2ant1 |  |-  ( ( ph /\ Z ( ~=c ` C ) h /\ h ( ~=c ` C ) ZZring ) -> ( Z ( ~=c ` C ) ZZring -> ( ZeroO ` C ) = (/) ) ) | 
						
							| 54 | 23 53 | mpd |  |-  ( ( ph /\ Z ( ~=c ` C ) h /\ h ( ~=c ` C ) ZZring ) -> ( ZeroO ` C ) = (/) ) | 
						
							| 55 | 54 | 3exp |  |-  ( ph -> ( Z ( ~=c ` C ) h -> ( h ( ~=c ` C ) ZZring -> ( ZeroO ` C ) = (/) ) ) ) | 
						
							| 56 | 55 | a1dd |  |-  ( ph -> ( Z ( ~=c ` C ) h -> ( h e. ( Base ` C ) -> ( h ( ~=c ` C ) ZZring -> ( ZeroO ` C ) = (/) ) ) ) ) | 
						
							| 57 | 56 | ad2antrr |  |-  ( ( ( ph /\ h e. ( TermO ` C ) ) /\ Z e. ( TermO ` C ) ) -> ( Z ( ~=c ` C ) h -> ( h e. ( Base ` C ) -> ( h ( ~=c ` C ) ZZring -> ( ZeroO ` C ) = (/) ) ) ) ) | 
						
							| 58 | 21 57 | mpd |  |-  ( ( ( ph /\ h e. ( TermO ` C ) ) /\ Z e. ( TermO ` C ) ) -> ( h e. ( Base ` C ) -> ( h ( ~=c ` C ) ZZring -> ( ZeroO ` C ) = (/) ) ) ) | 
						
							| 59 | 58 | exp31 |  |-  ( ph -> ( h e. ( TermO ` C ) -> ( Z e. ( TermO ` C ) -> ( h e. ( Base ` C ) -> ( h ( ~=c ` C ) ZZring -> ( ZeroO ` C ) = (/) ) ) ) ) ) | 
						
							| 60 | 59 | com34 |  |-  ( ph -> ( h e. ( TermO ` C ) -> ( h e. ( Base ` C ) -> ( Z e. ( TermO ` C ) -> ( h ( ~=c ` C ) ZZring -> ( ZeroO ` C ) = (/) ) ) ) ) ) | 
						
							| 61 | 60 | com25 |  |-  ( ph -> ( h ( ~=c ` C ) ZZring -> ( h e. ( Base ` C ) -> ( Z e. ( TermO ` C ) -> ( h e. ( TermO ` C ) -> ( ZeroO ` C ) = (/) ) ) ) ) ) | 
						
							| 62 | 61 | ad2antrr |  |-  ( ( ( ph /\ h e. ( InitO ` C ) ) /\ ZZring e. ( InitO ` C ) ) -> ( h ( ~=c ` C ) ZZring -> ( h e. ( Base ` C ) -> ( Z e. ( TermO ` C ) -> ( h e. ( TermO ` C ) -> ( ZeroO ` C ) = (/) ) ) ) ) ) | 
						
							| 63 | 17 62 | mpd |  |-  ( ( ( ph /\ h e. ( InitO ` C ) ) /\ ZZring e. ( InitO ` C ) ) -> ( h e. ( Base ` C ) -> ( Z e. ( TermO ` C ) -> ( h e. ( TermO ` C ) -> ( ZeroO ` C ) = (/) ) ) ) ) | 
						
							| 64 | 63 | ex |  |-  ( ( ph /\ h e. ( InitO ` C ) ) -> ( ZZring e. ( InitO ` C ) -> ( h e. ( Base ` C ) -> ( Z e. ( TermO ` C ) -> ( h e. ( TermO ` C ) -> ( ZeroO ` C ) = (/) ) ) ) ) ) | 
						
							| 65 | 64 | com25 |  |-  ( ( ph /\ h e. ( InitO ` C ) ) -> ( h e. ( TermO ` C ) -> ( h e. ( Base ` C ) -> ( Z e. ( TermO ` C ) -> ( ZZring e. ( InitO ` C ) -> ( ZeroO ` C ) = (/) ) ) ) ) ) | 
						
							| 66 | 65 | expimpd |  |-  ( ph -> ( ( h e. ( InitO ` C ) /\ h e. ( TermO ` C ) ) -> ( h e. ( Base ` C ) -> ( Z e. ( TermO ` C ) -> ( ZZring e. ( InitO ` C ) -> ( ZeroO ` C ) = (/) ) ) ) ) ) | 
						
							| 67 | 66 | com23 |  |-  ( ph -> ( h e. ( Base ` C ) -> ( ( h e. ( InitO ` C ) /\ h e. ( TermO ` C ) ) -> ( Z e. ( TermO ` C ) -> ( ZZring e. ( InitO ` C ) -> ( ZeroO ` C ) = (/) ) ) ) ) ) | 
						
							| 68 | 67 | impd |  |-  ( ph -> ( ( h e. ( Base ` C ) /\ ( h e. ( InitO ` C ) /\ h e. ( TermO ` C ) ) ) -> ( Z e. ( TermO ` C ) -> ( ZZring e. ( InitO ` C ) -> ( ZeroO ` C ) = (/) ) ) ) ) | 
						
							| 69 | 68 | com24 |  |-  ( ph -> ( ZZring e. ( InitO ` C ) -> ( Z e. ( TermO ` C ) -> ( ( h e. ( Base ` C ) /\ ( h e. ( InitO ` C ) /\ h e. ( TermO ` C ) ) ) -> ( ZeroO ` C ) = (/) ) ) ) ) | 
						
							| 70 | 13 69 | mpd |  |-  ( ph -> ( Z e. ( TermO ` C ) -> ( ( h e. ( Base ` C ) /\ ( h e. ( InitO ` C ) /\ h e. ( TermO ` C ) ) ) -> ( ZeroO ` C ) = (/) ) ) ) | 
						
							| 71 | 12 70 | mpd |  |-  ( ph -> ( ( h e. ( Base ` C ) /\ ( h e. ( InitO ` C ) /\ h e. ( TermO ` C ) ) ) -> ( ZeroO ` C ) = (/) ) ) | 
						
							| 72 | 71 | adantr |  |-  ( ( ph /\ h e. ( ZeroO ` C ) ) -> ( ( h e. ( Base ` C ) /\ ( h e. ( InitO ` C ) /\ h e. ( TermO ` C ) ) ) -> ( ZeroO ` C ) = (/) ) ) | 
						
							| 73 | 11 72 | mpd |  |-  ( ( ph /\ h e. ( ZeroO ` C ) ) -> ( ZeroO ` C ) = (/) ) | 
						
							| 74 | 73 | expcom |  |-  ( h e. ( ZeroO ` C ) -> ( ph -> ( ZeroO ` C ) = (/) ) ) | 
						
							| 75 | 74 | exlimiv |  |-  ( E. h h e. ( ZeroO ` C ) -> ( ph -> ( ZeroO ` C ) = (/) ) ) | 
						
							| 76 | 7 75 | sylbi |  |-  ( -. ( ZeroO ` C ) = (/) -> ( ph -> ( ZeroO ` C ) = (/) ) ) | 
						
							| 77 | 6 76 | pm2.61i |  |-  ( ph -> ( ZeroO ` C ) = (/) ) |