| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ausgr.1 |  |-  G = { <. v , e >. | e C_ { x e. ~P v | ( # ` x ) = 2 } } | 
						
							| 2 |  | fvex |  |-  ( Vtx ` H ) e. _V | 
						
							| 3 |  | fvex |  |-  ( Edg ` H ) e. _V | 
						
							| 4 | 1 | isausgr |  |-  ( ( ( Vtx ` H ) e. _V /\ ( Edg ` H ) e. _V ) -> ( ( Vtx ` H ) G ( Edg ` H ) <-> ( Edg ` H ) C_ { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } ) ) | 
						
							| 5 | 2 3 4 | mp2an |  |-  ( ( Vtx ` H ) G ( Edg ` H ) <-> ( Edg ` H ) C_ { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } ) | 
						
							| 6 |  | edgval |  |-  ( Edg ` H ) = ran ( iEdg ` H ) | 
						
							| 7 | 6 | a1i |  |-  ( H e. W -> ( Edg ` H ) = ran ( iEdg ` H ) ) | 
						
							| 8 | 7 | sseq1d |  |-  ( H e. W -> ( ( Edg ` H ) C_ { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } <-> ran ( iEdg ` H ) C_ { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } ) ) | 
						
							| 9 |  | funfn |  |-  ( Fun ( iEdg ` H ) <-> ( iEdg ` H ) Fn dom ( iEdg ` H ) ) | 
						
							| 10 | 9 | biimpi |  |-  ( Fun ( iEdg ` H ) -> ( iEdg ` H ) Fn dom ( iEdg ` H ) ) | 
						
							| 11 | 10 | 3ad2ant3 |  |-  ( ( H e. W /\ ran ( iEdg ` H ) C_ { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } /\ Fun ( iEdg ` H ) ) -> ( iEdg ` H ) Fn dom ( iEdg ` H ) ) | 
						
							| 12 |  | simp2 |  |-  ( ( H e. W /\ ran ( iEdg ` H ) C_ { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } /\ Fun ( iEdg ` H ) ) -> ran ( iEdg ` H ) C_ { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } ) | 
						
							| 13 |  | df-f |  |-  ( ( iEdg ` H ) : dom ( iEdg ` H ) --> { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } <-> ( ( iEdg ` H ) Fn dom ( iEdg ` H ) /\ ran ( iEdg ` H ) C_ { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } ) ) | 
						
							| 14 | 11 12 13 | sylanbrc |  |-  ( ( H e. W /\ ran ( iEdg ` H ) C_ { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } /\ Fun ( iEdg ` H ) ) -> ( iEdg ` H ) : dom ( iEdg ` H ) --> { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } ) | 
						
							| 15 | 14 | 3exp |  |-  ( H e. W -> ( ran ( iEdg ` H ) C_ { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } -> ( Fun ( iEdg ` H ) -> ( iEdg ` H ) : dom ( iEdg ` H ) --> { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } ) ) ) | 
						
							| 16 | 8 15 | sylbid |  |-  ( H e. W -> ( ( Edg ` H ) C_ { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } -> ( Fun ( iEdg ` H ) -> ( iEdg ` H ) : dom ( iEdg ` H ) --> { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } ) ) ) | 
						
							| 17 | 5 16 | biimtrid |  |-  ( H e. W -> ( ( Vtx ` H ) G ( Edg ` H ) -> ( Fun ( iEdg ` H ) -> ( iEdg ` H ) : dom ( iEdg ` H ) --> { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } ) ) ) | 
						
							| 18 | 17 | 3imp |  |-  ( ( H e. W /\ ( Vtx ` H ) G ( Edg ` H ) /\ Fun ( iEdg ` H ) ) -> ( iEdg ` H ) : dom ( iEdg ` H ) --> { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } ) | 
						
							| 19 |  | eqid |  |-  ( Vtx ` H ) = ( Vtx ` H ) | 
						
							| 20 |  | eqid |  |-  ( iEdg ` H ) = ( iEdg ` H ) | 
						
							| 21 | 19 20 | isumgrs |  |-  ( H e. W -> ( H e. UMGraph <-> ( iEdg ` H ) : dom ( iEdg ` H ) --> { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } ) ) | 
						
							| 22 | 21 | 3ad2ant1 |  |-  ( ( H e. W /\ ( Vtx ` H ) G ( Edg ` H ) /\ Fun ( iEdg ` H ) ) -> ( H e. UMGraph <-> ( iEdg ` H ) : dom ( iEdg ` H ) --> { x e. ~P ( Vtx ` H ) | ( # ` x ) = 2 } ) ) | 
						
							| 23 | 18 22 | mpbird |  |-  ( ( H e. W /\ ( Vtx ` H ) G ( Edg ` H ) /\ Fun ( iEdg ` H ) ) -> H e. UMGraph ) |