| Step | Hyp | Ref | Expression | 
						
							| 1 |  | eluz2b2 |  |-  ( X e. ( ZZ>= ` 2 ) <-> ( X e. NN /\ 1 < X ) ) | 
						
							| 2 |  | 4z |  |-  4 e. ZZ | 
						
							| 3 | 2 | a1i |  |-  ( ( ( X e. NN /\ 1 < X ) /\ X e/ Prime ) -> 4 e. ZZ ) | 
						
							| 4 |  | nnz |  |-  ( X e. NN -> X e. ZZ ) | 
						
							| 5 | 4 | ad2antrr |  |-  ( ( ( X e. NN /\ 1 < X ) /\ X e/ Prime ) -> X e. ZZ ) | 
						
							| 6 |  | 1z |  |-  1 e. ZZ | 
						
							| 7 |  | zltp1le |  |-  ( ( 1 e. ZZ /\ X e. ZZ ) -> ( 1 < X <-> ( 1 + 1 ) <_ X ) ) | 
						
							| 8 | 6 4 7 | sylancr |  |-  ( X e. NN -> ( 1 < X <-> ( 1 + 1 ) <_ X ) ) | 
						
							| 9 |  | 1p1e2 |  |-  ( 1 + 1 ) = 2 | 
						
							| 10 | 9 | breq1i |  |-  ( ( 1 + 1 ) <_ X <-> 2 <_ X ) | 
						
							| 11 | 8 10 | bitrdi |  |-  ( X e. NN -> ( 1 < X <-> 2 <_ X ) ) | 
						
							| 12 |  | 2re |  |-  2 e. RR | 
						
							| 13 |  | nnre |  |-  ( X e. NN -> X e. RR ) | 
						
							| 14 |  | leloe |  |-  ( ( 2 e. RR /\ X e. RR ) -> ( 2 <_ X <-> ( 2 < X \/ 2 = X ) ) ) | 
						
							| 15 | 12 13 14 | sylancr |  |-  ( X e. NN -> ( 2 <_ X <-> ( 2 < X \/ 2 = X ) ) ) | 
						
							| 16 |  | 2z |  |-  2 e. ZZ | 
						
							| 17 |  | zltp1le |  |-  ( ( 2 e. ZZ /\ X e. ZZ ) -> ( 2 < X <-> ( 2 + 1 ) <_ X ) ) | 
						
							| 18 | 16 4 17 | sylancr |  |-  ( X e. NN -> ( 2 < X <-> ( 2 + 1 ) <_ X ) ) | 
						
							| 19 |  | 2p1e3 |  |-  ( 2 + 1 ) = 3 | 
						
							| 20 | 19 | breq1i |  |-  ( ( 2 + 1 ) <_ X <-> 3 <_ X ) | 
						
							| 21 | 18 20 | bitrdi |  |-  ( X e. NN -> ( 2 < X <-> 3 <_ X ) ) | 
						
							| 22 |  | 3re |  |-  3 e. RR | 
						
							| 23 |  | leloe |  |-  ( ( 3 e. RR /\ X e. RR ) -> ( 3 <_ X <-> ( 3 < X \/ 3 = X ) ) ) | 
						
							| 24 | 22 13 23 | sylancr |  |-  ( X e. NN -> ( 3 <_ X <-> ( 3 < X \/ 3 = X ) ) ) | 
						
							| 25 |  | df-4 |  |-  4 = ( 3 + 1 ) | 
						
							| 26 |  | 3z |  |-  3 e. ZZ | 
						
							| 27 |  | zltp1le |  |-  ( ( 3 e. ZZ /\ X e. ZZ ) -> ( 3 < X <-> ( 3 + 1 ) <_ X ) ) | 
						
							| 28 | 26 4 27 | sylancr |  |-  ( X e. NN -> ( 3 < X <-> ( 3 + 1 ) <_ X ) ) | 
						
							| 29 | 28 | biimpa |  |-  ( ( X e. NN /\ 3 < X ) -> ( 3 + 1 ) <_ X ) | 
						
							| 30 | 25 29 | eqbrtrid |  |-  ( ( X e. NN /\ 3 < X ) -> 4 <_ X ) | 
						
							| 31 | 30 | a1d |  |-  ( ( X e. NN /\ 3 < X ) -> ( X e/ Prime -> 4 <_ X ) ) | 
						
							| 32 | 31 | ex |  |-  ( X e. NN -> ( 3 < X -> ( X e/ Prime -> 4 <_ X ) ) ) | 
						
							| 33 |  | neleq1 |  |-  ( X = 3 -> ( X e/ Prime <-> 3 e/ Prime ) ) | 
						
							| 34 | 33 | eqcoms |  |-  ( 3 = X -> ( X e/ Prime <-> 3 e/ Prime ) ) | 
						
							| 35 |  | 3prm |  |-  3 e. Prime | 
						
							| 36 |  | pm2.24nel |  |-  ( 3 e. Prime -> ( 3 e/ Prime -> 4 <_ X ) ) | 
						
							| 37 | 35 36 | mp1i |  |-  ( 3 = X -> ( 3 e/ Prime -> 4 <_ X ) ) | 
						
							| 38 | 34 37 | sylbid |  |-  ( 3 = X -> ( X e/ Prime -> 4 <_ X ) ) | 
						
							| 39 | 38 | a1i |  |-  ( X e. NN -> ( 3 = X -> ( X e/ Prime -> 4 <_ X ) ) ) | 
						
							| 40 | 32 39 | jaod |  |-  ( X e. NN -> ( ( 3 < X \/ 3 = X ) -> ( X e/ Prime -> 4 <_ X ) ) ) | 
						
							| 41 | 24 40 | sylbid |  |-  ( X e. NN -> ( 3 <_ X -> ( X e/ Prime -> 4 <_ X ) ) ) | 
						
							| 42 | 21 41 | sylbid |  |-  ( X e. NN -> ( 2 < X -> ( X e/ Prime -> 4 <_ X ) ) ) | 
						
							| 43 |  | neleq1 |  |-  ( X = 2 -> ( X e/ Prime <-> 2 e/ Prime ) ) | 
						
							| 44 | 43 | eqcoms |  |-  ( 2 = X -> ( X e/ Prime <-> 2 e/ Prime ) ) | 
						
							| 45 |  | 2prm |  |-  2 e. Prime | 
						
							| 46 |  | pm2.24nel |  |-  ( 2 e. Prime -> ( 2 e/ Prime -> 4 <_ X ) ) | 
						
							| 47 | 45 46 | mp1i |  |-  ( 2 = X -> ( 2 e/ Prime -> 4 <_ X ) ) | 
						
							| 48 | 44 47 | sylbid |  |-  ( 2 = X -> ( X e/ Prime -> 4 <_ X ) ) | 
						
							| 49 | 48 | a1i |  |-  ( X e. NN -> ( 2 = X -> ( X e/ Prime -> 4 <_ X ) ) ) | 
						
							| 50 | 42 49 | jaod |  |-  ( X e. NN -> ( ( 2 < X \/ 2 = X ) -> ( X e/ Prime -> 4 <_ X ) ) ) | 
						
							| 51 | 15 50 | sylbid |  |-  ( X e. NN -> ( 2 <_ X -> ( X e/ Prime -> 4 <_ X ) ) ) | 
						
							| 52 | 11 51 | sylbid |  |-  ( X e. NN -> ( 1 < X -> ( X e/ Prime -> 4 <_ X ) ) ) | 
						
							| 53 | 52 | imp |  |-  ( ( X e. NN /\ 1 < X ) -> ( X e/ Prime -> 4 <_ X ) ) | 
						
							| 54 | 53 | imp |  |-  ( ( ( X e. NN /\ 1 < X ) /\ X e/ Prime ) -> 4 <_ X ) | 
						
							| 55 | 3 5 54 | 3jca |  |-  ( ( ( X e. NN /\ 1 < X ) /\ X e/ Prime ) -> ( 4 e. ZZ /\ X e. ZZ /\ 4 <_ X ) ) | 
						
							| 56 | 55 | ex |  |-  ( ( X e. NN /\ 1 < X ) -> ( X e/ Prime -> ( 4 e. ZZ /\ X e. ZZ /\ 4 <_ X ) ) ) | 
						
							| 57 |  | eluz2 |  |-  ( X e. ( ZZ>= ` 4 ) <-> ( 4 e. ZZ /\ X e. ZZ /\ 4 <_ X ) ) | 
						
							| 58 | 56 57 | imbitrrdi |  |-  ( ( X e. NN /\ 1 < X ) -> ( X e/ Prime -> X e. ( ZZ>= ` 4 ) ) ) | 
						
							| 59 | 1 58 | sylbi |  |-  ( X e. ( ZZ>= ` 2 ) -> ( X e/ Prime -> X e. ( ZZ>= ` 4 ) ) ) | 
						
							| 60 | 59 | imp |  |-  ( ( X e. ( ZZ>= ` 2 ) /\ X e/ Prime ) -> X e. ( ZZ>= ` 4 ) ) |