| 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  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  →  ( 𝐼 ‘ 𝑄 )  ⊆  ( Base ‘ ( ( DVecH ‘ 𝐾 ) ‘ 𝑊 ) ) ) | 
						
							| 9 |  | eqid | ⊢ ( ( TEndo ‘ 𝐾 ) ‘ 𝑊 )  =  ( ( TEndo ‘ 𝐾 ) ‘ 𝑊 ) | 
						
							| 10 | 3 4 9 6 7 | dvhvbase | ⊢ ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  →  ( Base ‘ ( ( DVecH ‘ 𝐾 ) ‘ 𝑊 ) )  =  ( 𝑇  ×  ( ( TEndo ‘ 𝐾 ) ‘ 𝑊 ) ) ) | 
						
							| 11 | 10 | adantr | ⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  →  ( Base ‘ ( ( DVecH ‘ 𝐾 ) ‘ 𝑊 ) )  =  ( 𝑇  ×  ( ( TEndo ‘ 𝐾 ) ‘ 𝑊 ) ) ) | 
						
							| 12 | 8 11 | sseqtrd | ⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  →  ( 𝐼 ‘ 𝑄 )  ⊆  ( 𝑇  ×  ( ( TEndo ‘ 𝐾 ) ‘ 𝑊 ) ) ) | 
						
							| 13 | 12 | sseld | ⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  →  ( 𝑌  ∈  ( 𝐼 ‘ 𝑄 )  →  𝑌  ∈  ( 𝑇  ×  ( ( TEndo ‘ 𝐾 ) ‘ 𝑊 ) ) ) ) | 
						
							| 14 | 13 | 3impia | ⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 )  ∧  𝑌  ∈  ( 𝐼 ‘ 𝑄 ) )  →  𝑌  ∈  ( 𝑇  ×  ( ( TEndo ‘ 𝐾 ) ‘ 𝑊 ) ) ) | 
						
							| 15 |  | xp1st | ⊢ ( 𝑌  ∈  ( 𝑇  ×  ( ( TEndo ‘ 𝐾 ) ‘ 𝑊 ) )  →  ( 1st  ‘ 𝑌 )  ∈  𝑇 ) | 
						
							| 16 | 14 15 | syl | ⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 )  ∧  𝑌  ∈  ( 𝐼 ‘ 𝑄 ) )  →  ( 1st  ‘ 𝑌 )  ∈  𝑇 ) |