| Step | Hyp | Ref | Expression | 
						
							| 1 |  | elreal |  |-  ( A e. RR <-> E. x e. R. <. x , 0R >. = A ) | 
						
							| 2 |  | elreal |  |-  ( B e. RR <-> E. y e. R. <. y , 0R >. = B ) | 
						
							| 3 |  | elreal |  |-  ( C e. RR <-> E. z e. R. <. z , 0R >. = C ) | 
						
							| 4 |  | breq1 |  |-  ( <. x , 0R >. = A -> ( <. x , 0R >. . <-> A . ) ) | 
						
							| 5 | 4 | anbi1d |  |-  ( <. x , 0R >. = A -> ( ( <. x , 0R >. . /\ <. y , 0R >. . ) <-> ( A . /\ <. y , 0R >. . ) ) ) | 
						
							| 6 |  | breq1 |  |-  ( <. x , 0R >. = A -> ( <. x , 0R >. . <-> A . ) ) | 
						
							| 7 | 5 6 | imbi12d |  |-  ( <. x , 0R >. = A -> ( ( ( <. x , 0R >. . /\ <. y , 0R >. . ) -> <. x , 0R >. . ) <-> ( ( A . /\ <. y , 0R >. . ) -> A . ) ) ) | 
						
							| 8 |  | breq2 |  |-  ( <. y , 0R >. = B -> ( A . <-> A  | 
						
							| 9 |  | breq1 |  |-  ( <. y , 0R >. = B -> ( <. y , 0R >. . <-> B . ) ) | 
						
							| 10 | 8 9 | anbi12d |  |-  ( <. y , 0R >. = B -> ( ( A . /\ <. y , 0R >. . ) <-> ( A . ) ) ) | 
						
							| 11 | 10 | imbi1d |  |-  ( <. y , 0R >. = B -> ( ( ( A . /\ <. y , 0R >. . ) -> A . ) <-> ( ( A . ) -> A . ) ) ) | 
						
							| 12 |  | breq2 |  |-  ( <. z , 0R >. = C -> ( B . <-> B  | 
						
							| 13 | 12 | anbi2d |  |-  ( <. z , 0R >. = C -> ( ( A . ) <-> ( A  | 
						
							| 14 |  | breq2 |  |-  ( <. z , 0R >. = C -> ( A . <-> A  | 
						
							| 15 | 13 14 | imbi12d |  |-  ( <. z , 0R >. = C -> ( ( ( A . ) -> A . ) <-> ( ( A  A  | 
						
							| 16 |  | ltresr |  |-  ( <. x , 0R >. . <-> x  | 
						
							| 17 |  | ltresr |  |-  ( <. y , 0R >. . <-> y  | 
						
							| 18 |  | ltsosr |  |-   | 
						
							| 19 |  | ltrelsr |  |-   | 
						
							| 20 | 18 19 | sotri |  |-  ( ( x  x  | 
						
							| 21 | 16 17 20 | syl2anb |  |-  ( ( <. x , 0R >. . /\ <. y , 0R >. . ) -> x  | 
						
							| 22 |  | ltresr |  |-  ( <. x , 0R >. . <-> x  | 
						
							| 23 | 21 22 | sylibr |  |-  ( ( <. x , 0R >. . /\ <. y , 0R >. . ) -> <. x , 0R >. . ) | 
						
							| 24 | 23 | a1i |  |-  ( ( x e. R. /\ y e. R. /\ z e. R. ) -> ( ( <. x , 0R >. . /\ <. y , 0R >. . ) -> <. x , 0R >. . ) ) | 
						
							| 25 | 1 2 3 7 11 15 24 | 3gencl |  |-  ( ( A e. RR /\ B e. RR /\ C e. RR ) -> ( ( A  A  |