| Step | Hyp | Ref | Expression | 
						
							| 1 |  | dicelval1st.l |  |-  .<_ = ( le ` K ) | 
						
							| 2 |  | dicelval1st.a |  |-  A = ( Atoms ` K ) | 
						
							| 3 |  | dicelval1st.h |  |-  H = ( LHyp ` K ) | 
						
							| 4 |  | dicelval1st.t |  |-  T = ( ( LTrn ` K ) ` W ) | 
						
							| 5 |  | dicelval1st.i |  |-  I = ( ( DIsoC ` K ) ` W ) | 
						
							| 6 |  | eqid |  |-  ( ( DVecH ` K ) ` W ) = ( ( DVecH ` K ) ` W ) | 
						
							| 7 |  | eqid |  |-  ( Base ` ( ( DVecH ` K ) ` W ) ) = ( Base ` ( ( DVecH ` K ) ` W ) ) | 
						
							| 8 | 1 2 3 5 6 7 | dicssdvh |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( Q e. A /\ -. Q .<_ W ) ) -> ( I ` Q ) C_ ( Base ` ( ( DVecH ` K ) ` W ) ) ) | 
						
							| 9 |  | eqid |  |-  ( ( TEndo ` K ) ` W ) = ( ( TEndo ` K ) ` W ) | 
						
							| 10 | 3 4 9 6 7 | dvhvbase |  |-  ( ( K e. HL /\ W e. H ) -> ( Base ` ( ( DVecH ` K ) ` W ) ) = ( T X. ( ( TEndo ` K ) ` W ) ) ) | 
						
							| 11 | 10 | adantr |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( Q e. A /\ -. Q .<_ W ) ) -> ( Base ` ( ( DVecH ` K ) ` W ) ) = ( T X. ( ( TEndo ` K ) ` W ) ) ) | 
						
							| 12 | 8 11 | sseqtrd |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( Q e. A /\ -. Q .<_ W ) ) -> ( I ` Q ) C_ ( T X. ( ( TEndo ` K ) ` W ) ) ) | 
						
							| 13 | 12 | sseld |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( Q e. A /\ -. Q .<_ W ) ) -> ( Y e. ( I ` Q ) -> Y e. ( T X. ( ( TEndo ` K ) ` W ) ) ) ) | 
						
							| 14 | 13 | 3impia |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( Q e. A /\ -. Q .<_ W ) /\ Y e. ( I ` Q ) ) -> Y e. ( T X. ( ( TEndo ` K ) ` W ) ) ) | 
						
							| 15 |  | xp1st |  |-  ( Y e. ( T X. ( ( TEndo ` K ) ` W ) ) -> ( 1st ` Y ) e. T ) | 
						
							| 16 | 14 15 | syl |  |-  ( ( ( K e. HL /\ W e. H ) /\ ( Q e. A /\ -. Q .<_ W ) /\ Y e. ( I ` Q ) ) -> ( 1st ` Y ) e. T ) |