| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ftc2ditg.x |  |-  ( ph -> X e. RR ) | 
						
							| 2 |  | ftc2ditg.y |  |-  ( ph -> Y e. RR ) | 
						
							| 3 |  | ftc2ditg.a |  |-  ( ph -> A e. ( X [,] Y ) ) | 
						
							| 4 |  | ftc2ditg.b |  |-  ( ph -> B e. ( X [,] Y ) ) | 
						
							| 5 |  | ftc2ditg.c |  |-  ( ph -> ( RR _D F ) e. ( ( X (,) Y ) -cn-> CC ) ) | 
						
							| 6 |  | ftc2ditg.i |  |-  ( ph -> ( RR _D F ) e. L^1 ) | 
						
							| 7 |  | ftc2ditg.f |  |-  ( ph -> F e. ( ( X [,] Y ) -cn-> CC ) ) | 
						
							| 8 |  | iccssre |  |-  ( ( X e. RR /\ Y e. RR ) -> ( X [,] Y ) C_ RR ) | 
						
							| 9 | 1 2 8 | syl2anc |  |-  ( ph -> ( X [,] Y ) C_ RR ) | 
						
							| 10 | 9 3 | sseldd |  |-  ( ph -> A e. RR ) | 
						
							| 11 | 9 4 | sseldd |  |-  ( ph -> B e. RR ) | 
						
							| 12 | 1 2 3 4 5 6 7 | ftc2ditglem |  |-  ( ( ph /\ A <_ B ) -> S_ [ A -> B ] ( ( RR _D F ) ` t ) _d t = ( ( F ` B ) - ( F ` A ) ) ) | 
						
							| 13 |  | fvexd |  |-  ( ( ph /\ t e. ( X (,) Y ) ) -> ( ( RR _D F ) ` t ) e. _V ) | 
						
							| 14 |  | cncff |  |-  ( ( RR _D F ) e. ( ( X (,) Y ) -cn-> CC ) -> ( RR _D F ) : ( X (,) Y ) --> CC ) | 
						
							| 15 | 5 14 | syl |  |-  ( ph -> ( RR _D F ) : ( X (,) Y ) --> CC ) | 
						
							| 16 | 15 | feqmptd |  |-  ( ph -> ( RR _D F ) = ( t e. ( X (,) Y ) |-> ( ( RR _D F ) ` t ) ) ) | 
						
							| 17 | 16 6 | eqeltrrd |  |-  ( ph -> ( t e. ( X (,) Y ) |-> ( ( RR _D F ) ` t ) ) e. L^1 ) | 
						
							| 18 | 1 2 4 3 13 17 | ditgswap |  |-  ( ph -> S_ [ A -> B ] ( ( RR _D F ) ` t ) _d t = -u S_ [ B -> A ] ( ( RR _D F ) ` t ) _d t ) | 
						
							| 19 | 18 | adantr |  |-  ( ( ph /\ B <_ A ) -> S_ [ A -> B ] ( ( RR _D F ) ` t ) _d t = -u S_ [ B -> A ] ( ( RR _D F ) ` t ) _d t ) | 
						
							| 20 | 1 2 4 3 5 6 7 | ftc2ditglem |  |-  ( ( ph /\ B <_ A ) -> S_ [ B -> A ] ( ( RR _D F ) ` t ) _d t = ( ( F ` A ) - ( F ` B ) ) ) | 
						
							| 21 | 20 | negeqd |  |-  ( ( ph /\ B <_ A ) -> -u S_ [ B -> A ] ( ( RR _D F ) ` t ) _d t = -u ( ( F ` A ) - ( F ` B ) ) ) | 
						
							| 22 |  | cncff |  |-  ( F e. ( ( X [,] Y ) -cn-> CC ) -> F : ( X [,] Y ) --> CC ) | 
						
							| 23 | 7 22 | syl |  |-  ( ph -> F : ( X [,] Y ) --> CC ) | 
						
							| 24 | 23 3 | ffvelcdmd |  |-  ( ph -> ( F ` A ) e. CC ) | 
						
							| 25 | 23 4 | ffvelcdmd |  |-  ( ph -> ( F ` B ) e. CC ) | 
						
							| 26 | 24 25 | negsubdi2d |  |-  ( ph -> -u ( ( F ` A ) - ( F ` B ) ) = ( ( F ` B ) - ( F ` A ) ) ) | 
						
							| 27 | 26 | adantr |  |-  ( ( ph /\ B <_ A ) -> -u ( ( F ` A ) - ( F ` B ) ) = ( ( F ` B ) - ( F ` A ) ) ) | 
						
							| 28 | 19 21 27 | 3eqtrd |  |-  ( ( ph /\ B <_ A ) -> S_ [ A -> B ] ( ( RR _D F ) ` t ) _d t = ( ( F ` B ) - ( F ` A ) ) ) | 
						
							| 29 | 10 11 12 28 | lecasei |  |-  ( ph -> S_ [ A -> B ] ( ( RR _D F ) ` t ) _d t = ( ( F ` B ) - ( F ` A ) ) ) |