| Step | Hyp | Ref | Expression | 
						
							| 1 |  | diaval.b |  | 
						
							| 2 |  | diaval.l |  | 
						
							| 3 |  | diaval.h |  | 
						
							| 4 |  | elex |  | 
						
							| 5 |  | fveq2 |  | 
						
							| 6 | 5 3 | eqtr4di |  | 
						
							| 7 |  | fveq2 |  | 
						
							| 8 | 7 1 | eqtr4di |  | 
						
							| 9 |  | fveq2 |  | 
						
							| 10 | 9 2 | eqtr4di |  | 
						
							| 11 | 10 | breqd |  | 
						
							| 12 | 8 11 | rabeqbidv |  | 
						
							| 13 |  | fveq2 |  | 
						
							| 14 | 13 | fveq1d |  | 
						
							| 15 |  | fveq2 |  | 
						
							| 16 | 15 | fveq1d |  | 
						
							| 17 | 16 | fveq1d |  | 
						
							| 18 |  | eqidd |  | 
						
							| 19 | 17 10 18 | breq123d |  | 
						
							| 20 | 14 19 | rabeqbidv |  | 
						
							| 21 | 12 20 | mpteq12dv |  | 
						
							| 22 | 6 21 | mpteq12dv |  | 
						
							| 23 |  | df-disoa |  | 
						
							| 24 | 22 23 3 | mptfvmpt |  | 
						
							| 25 | 4 24 | syl |  |