| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							0sno | 
							⊢  0s   ∈   No   | 
						
						
							| 2 | 
							
								
							 | 
							mulsval | 
							⊢ ( ( 𝐴  ∈   No   ∧   0s   ∈   No  )  →  ( 𝐴  ·s   0s  )  =  ( ( { 𝑎  ∣  ∃ 𝑝  ∈  (  L  ‘ 𝐴 ) ∃ 𝑞  ∈  (  L  ‘  0s  ) 𝑎  =  ( ( ( 𝑝  ·s   0s  )  +s  ( 𝐴  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) ) }  ∪  { 𝑏  ∣  ∃ 𝑟  ∈  (  R  ‘ 𝐴 ) ∃ 𝑠  ∈  (  R  ‘  0s  ) 𝑏  =  ( ( ( 𝑟  ·s   0s  )  +s  ( 𝐴  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) ) } )  |s  ( { 𝑐  ∣  ∃ 𝑡  ∈  (  L  ‘ 𝐴 ) ∃ 𝑢  ∈  (  R  ‘  0s  ) 𝑐  =  ( ( ( 𝑡  ·s   0s  )  +s  ( 𝐴  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) ) }  ∪  { 𝑑  ∣  ∃ 𝑣  ∈  (  R  ‘ 𝐴 ) ∃ 𝑤  ∈  (  L  ‘  0s  ) 𝑑  =  ( ( ( 𝑣  ·s   0s  )  +s  ( 𝐴  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) ) } ) ) )  | 
						
						
							| 3 | 
							
								1 2
							 | 
							mpan2 | 
							⊢ ( 𝐴  ∈   No   →  ( 𝐴  ·s   0s  )  =  ( ( { 𝑎  ∣  ∃ 𝑝  ∈  (  L  ‘ 𝐴 ) ∃ 𝑞  ∈  (  L  ‘  0s  ) 𝑎  =  ( ( ( 𝑝  ·s   0s  )  +s  ( 𝐴  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) ) }  ∪  { 𝑏  ∣  ∃ 𝑟  ∈  (  R  ‘ 𝐴 ) ∃ 𝑠  ∈  (  R  ‘  0s  ) 𝑏  =  ( ( ( 𝑟  ·s   0s  )  +s  ( 𝐴  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) ) } )  |s  ( { 𝑐  ∣  ∃ 𝑡  ∈  (  L  ‘ 𝐴 ) ∃ 𝑢  ∈  (  R  ‘  0s  ) 𝑐  =  ( ( ( 𝑡  ·s   0s  )  +s  ( 𝐴  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) ) }  ∪  { 𝑑  ∣  ∃ 𝑣  ∈  (  R  ‘ 𝐴 ) ∃ 𝑤  ∈  (  L  ‘  0s  ) 𝑑  =  ( ( ( 𝑣  ·s   0s  )  +s  ( 𝐴  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) ) } ) ) )  | 
						
						
							| 4 | 
							
								
							 | 
							rex0 | 
							⊢ ¬  ∃ 𝑞  ∈  ∅ 𝑎  =  ( ( ( 𝑝  ·s   0s  )  +s  ( 𝐴  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) )  | 
						
						
							| 5 | 
							
								
							 | 
							left0s | 
							⊢ (  L  ‘  0s  )  =  ∅  | 
						
						
							| 6 | 
							
								5
							 | 
							rexeqi | 
							⊢ ( ∃ 𝑞  ∈  (  L  ‘  0s  ) 𝑎  =  ( ( ( 𝑝  ·s   0s  )  +s  ( 𝐴  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) )  ↔  ∃ 𝑞  ∈  ∅ 𝑎  =  ( ( ( 𝑝  ·s   0s  )  +s  ( 𝐴  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) ) )  | 
						
						
							| 7 | 
							
								4 6
							 | 
							mtbir | 
							⊢ ¬  ∃ 𝑞  ∈  (  L  ‘  0s  ) 𝑎  =  ( ( ( 𝑝  ·s   0s  )  +s  ( 𝐴  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) )  | 
						
						
							| 8 | 
							
								7
							 | 
							a1i | 
							⊢ ( 𝑝  ∈  (  L  ‘ 𝐴 )  →  ¬  ∃ 𝑞  ∈  (  L  ‘  0s  ) 𝑎  =  ( ( ( 𝑝  ·s   0s  )  +s  ( 𝐴  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) ) )  | 
						
						
							| 9 | 
							
								8
							 | 
							nrex | 
							⊢ ¬  ∃ 𝑝  ∈  (  L  ‘ 𝐴 ) ∃ 𝑞  ∈  (  L  ‘  0s  ) 𝑎  =  ( ( ( 𝑝  ·s   0s  )  +s  ( 𝐴  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) )  | 
						
						
							| 10 | 
							
								9
							 | 
							abf | 
							⊢ { 𝑎  ∣  ∃ 𝑝  ∈  (  L  ‘ 𝐴 ) ∃ 𝑞  ∈  (  L  ‘  0s  ) 𝑎  =  ( ( ( 𝑝  ·s   0s  )  +s  ( 𝐴  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) ) }  =  ∅  | 
						
						
							| 11 | 
							
								
							 | 
							rex0 | 
							⊢ ¬  ∃ 𝑠  ∈  ∅ 𝑏  =  ( ( ( 𝑟  ·s   0s  )  +s  ( 𝐴  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) )  | 
						
						
							| 12 | 
							
								
							 | 
							right0s | 
							⊢ (  R  ‘  0s  )  =  ∅  | 
						
						
							| 13 | 
							
								12
							 | 
							rexeqi | 
							⊢ ( ∃ 𝑠  ∈  (  R  ‘  0s  ) 𝑏  =  ( ( ( 𝑟  ·s   0s  )  +s  ( 𝐴  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) )  ↔  ∃ 𝑠  ∈  ∅ 𝑏  =  ( ( ( 𝑟  ·s   0s  )  +s  ( 𝐴  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) ) )  | 
						
						
							| 14 | 
							
								11 13
							 | 
							mtbir | 
							⊢ ¬  ∃ 𝑠  ∈  (  R  ‘  0s  ) 𝑏  =  ( ( ( 𝑟  ·s   0s  )  +s  ( 𝐴  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) )  | 
						
						
							| 15 | 
							
								14
							 | 
							a1i | 
							⊢ ( 𝑟  ∈  (  R  ‘ 𝐴 )  →  ¬  ∃ 𝑠  ∈  (  R  ‘  0s  ) 𝑏  =  ( ( ( 𝑟  ·s   0s  )  +s  ( 𝐴  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) ) )  | 
						
						
							| 16 | 
							
								15
							 | 
							nrex | 
							⊢ ¬  ∃ 𝑟  ∈  (  R  ‘ 𝐴 ) ∃ 𝑠  ∈  (  R  ‘  0s  ) 𝑏  =  ( ( ( 𝑟  ·s   0s  )  +s  ( 𝐴  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) )  | 
						
						
							| 17 | 
							
								16
							 | 
							abf | 
							⊢ { 𝑏  ∣  ∃ 𝑟  ∈  (  R  ‘ 𝐴 ) ∃ 𝑠  ∈  (  R  ‘  0s  ) 𝑏  =  ( ( ( 𝑟  ·s   0s  )  +s  ( 𝐴  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) ) }  =  ∅  | 
						
						
							| 18 | 
							
								10 17
							 | 
							uneq12i | 
							⊢ ( { 𝑎  ∣  ∃ 𝑝  ∈  (  L  ‘ 𝐴 ) ∃ 𝑞  ∈  (  L  ‘  0s  ) 𝑎  =  ( ( ( 𝑝  ·s   0s  )  +s  ( 𝐴  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) ) }  ∪  { 𝑏  ∣  ∃ 𝑟  ∈  (  R  ‘ 𝐴 ) ∃ 𝑠  ∈  (  R  ‘  0s  ) 𝑏  =  ( ( ( 𝑟  ·s   0s  )  +s  ( 𝐴  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) ) } )  =  ( ∅  ∪  ∅ )  | 
						
						
							| 19 | 
							
								
							 | 
							un0 | 
							⊢ ( ∅  ∪  ∅ )  =  ∅  | 
						
						
							| 20 | 
							
								18 19
							 | 
							eqtri | 
							⊢ ( { 𝑎  ∣  ∃ 𝑝  ∈  (  L  ‘ 𝐴 ) ∃ 𝑞  ∈  (  L  ‘  0s  ) 𝑎  =  ( ( ( 𝑝  ·s   0s  )  +s  ( 𝐴  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) ) }  ∪  { 𝑏  ∣  ∃ 𝑟  ∈  (  R  ‘ 𝐴 ) ∃ 𝑠  ∈  (  R  ‘  0s  ) 𝑏  =  ( ( ( 𝑟  ·s   0s  )  +s  ( 𝐴  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) ) } )  =  ∅  | 
						
						
							| 21 | 
							
								
							 | 
							rex0 | 
							⊢ ¬  ∃ 𝑢  ∈  ∅ 𝑐  =  ( ( ( 𝑡  ·s   0s  )  +s  ( 𝐴  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) )  | 
						
						
							| 22 | 
							
								12
							 | 
							rexeqi | 
							⊢ ( ∃ 𝑢  ∈  (  R  ‘  0s  ) 𝑐  =  ( ( ( 𝑡  ·s   0s  )  +s  ( 𝐴  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) )  ↔  ∃ 𝑢  ∈  ∅ 𝑐  =  ( ( ( 𝑡  ·s   0s  )  +s  ( 𝐴  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) ) )  | 
						
						
							| 23 | 
							
								21 22
							 | 
							mtbir | 
							⊢ ¬  ∃ 𝑢  ∈  (  R  ‘  0s  ) 𝑐  =  ( ( ( 𝑡  ·s   0s  )  +s  ( 𝐴  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) )  | 
						
						
							| 24 | 
							
								23
							 | 
							a1i | 
							⊢ ( 𝑡  ∈  (  L  ‘ 𝐴 )  →  ¬  ∃ 𝑢  ∈  (  R  ‘  0s  ) 𝑐  =  ( ( ( 𝑡  ·s   0s  )  +s  ( 𝐴  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) ) )  | 
						
						
							| 25 | 
							
								24
							 | 
							nrex | 
							⊢ ¬  ∃ 𝑡  ∈  (  L  ‘ 𝐴 ) ∃ 𝑢  ∈  (  R  ‘  0s  ) 𝑐  =  ( ( ( 𝑡  ·s   0s  )  +s  ( 𝐴  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) )  | 
						
						
							| 26 | 
							
								25
							 | 
							abf | 
							⊢ { 𝑐  ∣  ∃ 𝑡  ∈  (  L  ‘ 𝐴 ) ∃ 𝑢  ∈  (  R  ‘  0s  ) 𝑐  =  ( ( ( 𝑡  ·s   0s  )  +s  ( 𝐴  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) ) }  =  ∅  | 
						
						
							| 27 | 
							
								
							 | 
							rex0 | 
							⊢ ¬  ∃ 𝑤  ∈  ∅ 𝑑  =  ( ( ( 𝑣  ·s   0s  )  +s  ( 𝐴  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) )  | 
						
						
							| 28 | 
							
								5
							 | 
							rexeqi | 
							⊢ ( ∃ 𝑤  ∈  (  L  ‘  0s  ) 𝑑  =  ( ( ( 𝑣  ·s   0s  )  +s  ( 𝐴  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) )  ↔  ∃ 𝑤  ∈  ∅ 𝑑  =  ( ( ( 𝑣  ·s   0s  )  +s  ( 𝐴  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) ) )  | 
						
						
							| 29 | 
							
								27 28
							 | 
							mtbir | 
							⊢ ¬  ∃ 𝑤  ∈  (  L  ‘  0s  ) 𝑑  =  ( ( ( 𝑣  ·s   0s  )  +s  ( 𝐴  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) )  | 
						
						
							| 30 | 
							
								29
							 | 
							a1i | 
							⊢ ( 𝑣  ∈  (  R  ‘ 𝐴 )  →  ¬  ∃ 𝑤  ∈  (  L  ‘  0s  ) 𝑑  =  ( ( ( 𝑣  ·s   0s  )  +s  ( 𝐴  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) ) )  | 
						
						
							| 31 | 
							
								30
							 | 
							nrex | 
							⊢ ¬  ∃ 𝑣  ∈  (  R  ‘ 𝐴 ) ∃ 𝑤  ∈  (  L  ‘  0s  ) 𝑑  =  ( ( ( 𝑣  ·s   0s  )  +s  ( 𝐴  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) )  | 
						
						
							| 32 | 
							
								31
							 | 
							abf | 
							⊢ { 𝑑  ∣  ∃ 𝑣  ∈  (  R  ‘ 𝐴 ) ∃ 𝑤  ∈  (  L  ‘  0s  ) 𝑑  =  ( ( ( 𝑣  ·s   0s  )  +s  ( 𝐴  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) ) }  =  ∅  | 
						
						
							| 33 | 
							
								26 32
							 | 
							uneq12i | 
							⊢ ( { 𝑐  ∣  ∃ 𝑡  ∈  (  L  ‘ 𝐴 ) ∃ 𝑢  ∈  (  R  ‘  0s  ) 𝑐  =  ( ( ( 𝑡  ·s   0s  )  +s  ( 𝐴  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) ) }  ∪  { 𝑑  ∣  ∃ 𝑣  ∈  (  R  ‘ 𝐴 ) ∃ 𝑤  ∈  (  L  ‘  0s  ) 𝑑  =  ( ( ( 𝑣  ·s   0s  )  +s  ( 𝐴  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) ) } )  =  ( ∅  ∪  ∅ )  | 
						
						
							| 34 | 
							
								33 19
							 | 
							eqtri | 
							⊢ ( { 𝑐  ∣  ∃ 𝑡  ∈  (  L  ‘ 𝐴 ) ∃ 𝑢  ∈  (  R  ‘  0s  ) 𝑐  =  ( ( ( 𝑡  ·s   0s  )  +s  ( 𝐴  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) ) }  ∪  { 𝑑  ∣  ∃ 𝑣  ∈  (  R  ‘ 𝐴 ) ∃ 𝑤  ∈  (  L  ‘  0s  ) 𝑑  =  ( ( ( 𝑣  ·s   0s  )  +s  ( 𝐴  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) ) } )  =  ∅  | 
						
						
							| 35 | 
							
								20 34
							 | 
							oveq12i | 
							⊢ ( ( { 𝑎  ∣  ∃ 𝑝  ∈  (  L  ‘ 𝐴 ) ∃ 𝑞  ∈  (  L  ‘  0s  ) 𝑎  =  ( ( ( 𝑝  ·s   0s  )  +s  ( 𝐴  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) ) }  ∪  { 𝑏  ∣  ∃ 𝑟  ∈  (  R  ‘ 𝐴 ) ∃ 𝑠  ∈  (  R  ‘  0s  ) 𝑏  =  ( ( ( 𝑟  ·s   0s  )  +s  ( 𝐴  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) ) } )  |s  ( { 𝑐  ∣  ∃ 𝑡  ∈  (  L  ‘ 𝐴 ) ∃ 𝑢  ∈  (  R  ‘  0s  ) 𝑐  =  ( ( ( 𝑡  ·s   0s  )  +s  ( 𝐴  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) ) }  ∪  { 𝑑  ∣  ∃ 𝑣  ∈  (  R  ‘ 𝐴 ) ∃ 𝑤  ∈  (  L  ‘  0s  ) 𝑑  =  ( ( ( 𝑣  ·s   0s  )  +s  ( 𝐴  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) ) } ) )  =  ( ∅  |s  ∅ )  | 
						
						
							| 36 | 
							
								
							 | 
							df-0s | 
							⊢  0s   =  ( ∅  |s  ∅ )  | 
						
						
							| 37 | 
							
								35 36
							 | 
							eqtr4i | 
							⊢ ( ( { 𝑎  ∣  ∃ 𝑝  ∈  (  L  ‘ 𝐴 ) ∃ 𝑞  ∈  (  L  ‘  0s  ) 𝑎  =  ( ( ( 𝑝  ·s   0s  )  +s  ( 𝐴  ·s  𝑞 ) )  -s  ( 𝑝  ·s  𝑞 ) ) }  ∪  { 𝑏  ∣  ∃ 𝑟  ∈  (  R  ‘ 𝐴 ) ∃ 𝑠  ∈  (  R  ‘  0s  ) 𝑏  =  ( ( ( 𝑟  ·s   0s  )  +s  ( 𝐴  ·s  𝑠 ) )  -s  ( 𝑟  ·s  𝑠 ) ) } )  |s  ( { 𝑐  ∣  ∃ 𝑡  ∈  (  L  ‘ 𝐴 ) ∃ 𝑢  ∈  (  R  ‘  0s  ) 𝑐  =  ( ( ( 𝑡  ·s   0s  )  +s  ( 𝐴  ·s  𝑢 ) )  -s  ( 𝑡  ·s  𝑢 ) ) }  ∪  { 𝑑  ∣  ∃ 𝑣  ∈  (  R  ‘ 𝐴 ) ∃ 𝑤  ∈  (  L  ‘  0s  ) 𝑑  =  ( ( ( 𝑣  ·s   0s  )  +s  ( 𝐴  ·s  𝑤 ) )  -s  ( 𝑣  ·s  𝑤 ) ) } ) )  =   0s   | 
						
						
							| 38 | 
							
								3 37
							 | 
							eqtrdi | 
							⊢ ( 𝐴  ∈   No   →  ( 𝐴  ·s   0s  )  =   0s  )  |