| Step | Hyp | Ref | Expression | 
						
							| 1 |  | rrx2pnecoorneor.i |  |-  I = { 1 , 2 } | 
						
							| 2 |  | rrx2pnecoorneor.b |  |-  P = ( RR ^m I ) | 
						
							| 3 |  | rrx2pnedifcoorneor.a |  |-  A = ( ( Y ` 1 ) - ( X ` 1 ) ) | 
						
							| 4 |  | rrx2pnedifcoorneorr.b |  |-  B = ( ( X ` 2 ) - ( Y ` 2 ) ) | 
						
							| 5 |  | eqid |  |-  ( ( Y ` 2 ) - ( X ` 2 ) ) = ( ( Y ` 2 ) - ( X ` 2 ) ) | 
						
							| 6 | 1 2 3 5 | rrx2pnedifcoorneor |  |-  ( ( X e. P /\ Y e. P /\ X =/= Y ) -> ( A =/= 0 \/ ( ( Y ` 2 ) - ( X ` 2 ) ) =/= 0 ) ) | 
						
							| 7 |  | eqcom |  |-  ( ( Y ` 2 ) = ( X ` 2 ) <-> ( X ` 2 ) = ( Y ` 2 ) ) | 
						
							| 8 | 7 | a1i |  |-  ( ( X e. P /\ Y e. P /\ X =/= Y ) -> ( ( Y ` 2 ) = ( X ` 2 ) <-> ( X ` 2 ) = ( Y ` 2 ) ) ) | 
						
							| 9 | 1 2 | rrx2pyel |  |-  ( X e. P -> ( X ` 2 ) e. RR ) | 
						
							| 10 | 9 | recnd |  |-  ( X e. P -> ( X ` 2 ) e. CC ) | 
						
							| 11 | 1 2 | rrx2pyel |  |-  ( Y e. P -> ( Y ` 2 ) e. RR ) | 
						
							| 12 | 11 | recnd |  |-  ( Y e. P -> ( Y ` 2 ) e. CC ) | 
						
							| 13 | 10 12 | anim12i |  |-  ( ( X e. P /\ Y e. P ) -> ( ( X ` 2 ) e. CC /\ ( Y ` 2 ) e. CC ) ) | 
						
							| 14 | 13 | ancomd |  |-  ( ( X e. P /\ Y e. P ) -> ( ( Y ` 2 ) e. CC /\ ( X ` 2 ) e. CC ) ) | 
						
							| 15 | 14 | 3adant3 |  |-  ( ( X e. P /\ Y e. P /\ X =/= Y ) -> ( ( Y ` 2 ) e. CC /\ ( X ` 2 ) e. CC ) ) | 
						
							| 16 |  | subeq0 |  |-  ( ( ( Y ` 2 ) e. CC /\ ( X ` 2 ) e. CC ) -> ( ( ( Y ` 2 ) - ( X ` 2 ) ) = 0 <-> ( Y ` 2 ) = ( X ` 2 ) ) ) | 
						
							| 17 | 15 16 | syl |  |-  ( ( X e. P /\ Y e. P /\ X =/= Y ) -> ( ( ( Y ` 2 ) - ( X ` 2 ) ) = 0 <-> ( Y ` 2 ) = ( X ` 2 ) ) ) | 
						
							| 18 | 13 | 3adant3 |  |-  ( ( X e. P /\ Y e. P /\ X =/= Y ) -> ( ( X ` 2 ) e. CC /\ ( Y ` 2 ) e. CC ) ) | 
						
							| 19 |  | subeq0 |  |-  ( ( ( X ` 2 ) e. CC /\ ( Y ` 2 ) e. CC ) -> ( ( ( X ` 2 ) - ( Y ` 2 ) ) = 0 <-> ( X ` 2 ) = ( Y ` 2 ) ) ) | 
						
							| 20 | 18 19 | syl |  |-  ( ( X e. P /\ Y e. P /\ X =/= Y ) -> ( ( ( X ` 2 ) - ( Y ` 2 ) ) = 0 <-> ( X ` 2 ) = ( Y ` 2 ) ) ) | 
						
							| 21 | 8 17 20 | 3bitr4d |  |-  ( ( X e. P /\ Y e. P /\ X =/= Y ) -> ( ( ( Y ` 2 ) - ( X ` 2 ) ) = 0 <-> ( ( X ` 2 ) - ( Y ` 2 ) ) = 0 ) ) | 
						
							| 22 | 4 | eqcomi |  |-  ( ( X ` 2 ) - ( Y ` 2 ) ) = B | 
						
							| 23 | 22 | eqeq1i |  |-  ( ( ( X ` 2 ) - ( Y ` 2 ) ) = 0 <-> B = 0 ) | 
						
							| 24 | 21 23 | bitrdi |  |-  ( ( X e. P /\ Y e. P /\ X =/= Y ) -> ( ( ( Y ` 2 ) - ( X ` 2 ) ) = 0 <-> B = 0 ) ) | 
						
							| 25 | 24 | necon3bid |  |-  ( ( X e. P /\ Y e. P /\ X =/= Y ) -> ( ( ( Y ` 2 ) - ( X ` 2 ) ) =/= 0 <-> B =/= 0 ) ) | 
						
							| 26 | 25 | orbi2d |  |-  ( ( X e. P /\ Y e. P /\ X =/= Y ) -> ( ( A =/= 0 \/ ( ( Y ` 2 ) - ( X ` 2 ) ) =/= 0 ) <-> ( A =/= 0 \/ B =/= 0 ) ) ) | 
						
							| 27 | 6 26 | mpbid |  |-  ( ( X e. P /\ Y e. P /\ X =/= Y ) -> ( A =/= 0 \/ B =/= 0 ) ) |