| Step | Hyp | Ref | Expression | 
						
							| 1 |  | nnnn0 |  |-  ( N e. NN -> N e. NN0 ) | 
						
							| 2 |  | faccl |  |-  ( N e. NN0 -> ( ! ` N ) e. NN ) | 
						
							| 3 |  | elnnuz |  |-  ( ( ! ` N ) e. NN <-> ( ! ` N ) e. ( ZZ>= ` 1 ) ) | 
						
							| 4 |  | eluzp1p1 |  |-  ( ( ! ` N ) e. ( ZZ>= ` 1 ) -> ( ( ! ` N ) + 1 ) e. ( ZZ>= ` ( 1 + 1 ) ) ) | 
						
							| 5 |  | df-2 |  |-  2 = ( 1 + 1 ) | 
						
							| 6 | 5 | fveq2i |  |-  ( ZZ>= ` 2 ) = ( ZZ>= ` ( 1 + 1 ) ) | 
						
							| 7 | 4 6 | eleqtrrdi |  |-  ( ( ! ` N ) e. ( ZZ>= ` 1 ) -> ( ( ! ` N ) + 1 ) e. ( ZZ>= ` 2 ) ) | 
						
							| 8 | 3 7 | sylbi |  |-  ( ( ! ` N ) e. NN -> ( ( ! ` N ) + 1 ) e. ( ZZ>= ` 2 ) ) | 
						
							| 9 |  | exprmfct |  |-  ( ( ( ! ` N ) + 1 ) e. ( ZZ>= ` 2 ) -> E. p e. Prime p || ( ( ! ` N ) + 1 ) ) | 
						
							| 10 | 2 8 9 | 3syl |  |-  ( N e. NN0 -> E. p e. Prime p || ( ( ! ` N ) + 1 ) ) | 
						
							| 11 |  | prmz |  |-  ( p e. Prime -> p e. ZZ ) | 
						
							| 12 |  | nn0z |  |-  ( N e. NN0 -> N e. ZZ ) | 
						
							| 13 |  | eluz |  |-  ( ( p e. ZZ /\ N e. ZZ ) -> ( N e. ( ZZ>= ` p ) <-> p <_ N ) ) | 
						
							| 14 | 11 12 13 | syl2an |  |-  ( ( p e. Prime /\ N e. NN0 ) -> ( N e. ( ZZ>= ` p ) <-> p <_ N ) ) | 
						
							| 15 |  | prmuz2 |  |-  ( p e. Prime -> p e. ( ZZ>= ` 2 ) ) | 
						
							| 16 |  | eluz2b2 |  |-  ( p e. ( ZZ>= ` 2 ) <-> ( p e. NN /\ 1 < p ) ) | 
						
							| 17 | 15 16 | sylib |  |-  ( p e. Prime -> ( p e. NN /\ 1 < p ) ) | 
						
							| 18 | 17 | adantr |  |-  ( ( p e. Prime /\ N e. ( ZZ>= ` p ) ) -> ( p e. NN /\ 1 < p ) ) | 
						
							| 19 | 18 | simpld |  |-  ( ( p e. Prime /\ N e. ( ZZ>= ` p ) ) -> p e. NN ) | 
						
							| 20 | 19 | nnnn0d |  |-  ( ( p e. Prime /\ N e. ( ZZ>= ` p ) ) -> p e. NN0 ) | 
						
							| 21 |  | eluznn0 |  |-  ( ( p e. NN0 /\ N e. ( ZZ>= ` p ) ) -> N e. NN0 ) | 
						
							| 22 | 20 21 | sylancom |  |-  ( ( p e. Prime /\ N e. ( ZZ>= ` p ) ) -> N e. NN0 ) | 
						
							| 23 |  | nnz |  |-  ( ( ! ` N ) e. NN -> ( ! ` N ) e. ZZ ) | 
						
							| 24 | 22 2 23 | 3syl |  |-  ( ( p e. Prime /\ N e. ( ZZ>= ` p ) ) -> ( ! ` N ) e. ZZ ) | 
						
							| 25 | 18 | simprd |  |-  ( ( p e. Prime /\ N e. ( ZZ>= ` p ) ) -> 1 < p ) | 
						
							| 26 |  | dvdsfac |  |-  ( ( p e. NN /\ N e. ( ZZ>= ` p ) ) -> p || ( ! ` N ) ) | 
						
							| 27 | 19 26 | sylancom |  |-  ( ( p e. Prime /\ N e. ( ZZ>= ` p ) ) -> p || ( ! ` N ) ) | 
						
							| 28 |  | ndvdsp1 |  |-  ( ( ( ! ` N ) e. ZZ /\ p e. NN /\ 1 < p ) -> ( p || ( ! ` N ) -> -. p || ( ( ! ` N ) + 1 ) ) ) | 
						
							| 29 | 28 | imp |  |-  ( ( ( ( ! ` N ) e. ZZ /\ p e. NN /\ 1 < p ) /\ p || ( ! ` N ) ) -> -. p || ( ( ! ` N ) + 1 ) ) | 
						
							| 30 | 24 19 25 27 29 | syl31anc |  |-  ( ( p e. Prime /\ N e. ( ZZ>= ` p ) ) -> -. p || ( ( ! ` N ) + 1 ) ) | 
						
							| 31 | 30 | ex |  |-  ( p e. Prime -> ( N e. ( ZZ>= ` p ) -> -. p || ( ( ! ` N ) + 1 ) ) ) | 
						
							| 32 | 31 | adantr |  |-  ( ( p e. Prime /\ N e. NN0 ) -> ( N e. ( ZZ>= ` p ) -> -. p || ( ( ! ` N ) + 1 ) ) ) | 
						
							| 33 | 14 32 | sylbird |  |-  ( ( p e. Prime /\ N e. NN0 ) -> ( p <_ N -> -. p || ( ( ! ` N ) + 1 ) ) ) | 
						
							| 34 | 33 | con2d |  |-  ( ( p e. Prime /\ N e. NN0 ) -> ( p || ( ( ! ` N ) + 1 ) -> -. p <_ N ) ) | 
						
							| 35 | 34 | ancoms |  |-  ( ( N e. NN0 /\ p e. Prime ) -> ( p || ( ( ! ` N ) + 1 ) -> -. p <_ N ) ) | 
						
							| 36 |  | nn0re |  |-  ( N e. NN0 -> N e. RR ) | 
						
							| 37 | 11 | zred |  |-  ( p e. Prime -> p e. RR ) | 
						
							| 38 |  | ltnle |  |-  ( ( N e. RR /\ p e. RR ) -> ( N < p <-> -. p <_ N ) ) | 
						
							| 39 | 36 37 38 | syl2an |  |-  ( ( N e. NN0 /\ p e. Prime ) -> ( N < p <-> -. p <_ N ) ) | 
						
							| 40 | 35 39 | sylibrd |  |-  ( ( N e. NN0 /\ p e. Prime ) -> ( p || ( ( ! ` N ) + 1 ) -> N < p ) ) | 
						
							| 41 | 40 | reximdva |  |-  ( N e. NN0 -> ( E. p e. Prime p || ( ( ! ` N ) + 1 ) -> E. p e. Prime N < p ) ) | 
						
							| 42 | 10 41 | mpd |  |-  ( N e. NN0 -> E. p e. Prime N < p ) | 
						
							| 43 | 1 42 | syl |  |-  ( N e. NN -> E. p e. Prime N < p ) |