| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							sstr2 | 
							 |-  ( A C_ B -> ( B C_ x -> A C_ x ) )  | 
						
						
							| 2 | 
							
								1
							 | 
							adantr | 
							 |-  ( ( A C_ B /\ x e. SH ) -> ( B C_ x -> A C_ x ) )  | 
						
						
							| 3 | 
							
								2
							 | 
							ss2rabdv | 
							 |-  ( A C_ B -> { x e. SH | B C_ x } C_ { x e. SH | A C_ x } ) | 
						
						
							| 4 | 
							
								
							 | 
							intss | 
							 |-  ( { x e. SH | B C_ x } C_ { x e. SH | A C_ x } -> |^| { x e. SH | A C_ x } C_ |^| { x e. SH | B C_ x } ) | 
						
						
							| 5 | 
							
								3 4
							 | 
							syl | 
							 |-  ( A C_ B -> |^| { x e. SH | A C_ x } C_ |^| { x e. SH | B C_ x } ) | 
						
						
							| 6 | 
							
								5
							 | 
							adantl | 
							 |-  ( ( B C_ ~H /\ A C_ B ) -> |^| { x e. SH | A C_ x } C_ |^| { x e. SH | B C_ x } ) | 
						
						
							| 7 | 
							
								
							 | 
							sstr | 
							 |-  ( ( A C_ B /\ B C_ ~H ) -> A C_ ~H )  | 
						
						
							| 8 | 
							
								7
							 | 
							ancoms | 
							 |-  ( ( B C_ ~H /\ A C_ B ) -> A C_ ~H )  | 
						
						
							| 9 | 
							
								
							 | 
							spanval | 
							 |-  ( A C_ ~H -> ( span ` A ) = |^| { x e. SH | A C_ x } ) | 
						
						
							| 10 | 
							
								8 9
							 | 
							syl | 
							 |-  ( ( B C_ ~H /\ A C_ B ) -> ( span ` A ) = |^| { x e. SH | A C_ x } ) | 
						
						
							| 11 | 
							
								
							 | 
							spanval | 
							 |-  ( B C_ ~H -> ( span ` B ) = |^| { x e. SH | B C_ x } ) | 
						
						
							| 12 | 
							
								11
							 | 
							adantr | 
							 |-  ( ( B C_ ~H /\ A C_ B ) -> ( span ` B ) = |^| { x e. SH | B C_ x } ) | 
						
						
							| 13 | 
							
								6 10 12
							 | 
							3sstr4d | 
							 |-  ( ( B C_ ~H /\ A C_ B ) -> ( span ` A ) C_ ( span ` B ) )  |