Database ELEMENTARY GEOMETRY Tarskian Geometry Motions ismot  
				
		 
		
			
		 
		Description:   Property of being an isometry mapping to the same space.  In geometry,
       this is also called a motion.  (Contributed by Thierry Arnoux , 15-Dec-2019) 
		
			
				
					Ref 
					Expression 
				 
					
						Hypotheses 
						ismot.p ⊢  𝑃   =  ( Base ‘ 𝐺  )  
					
						ismot.m ⊢   −    =  ( dist ‘ 𝐺  )  
				
					Assertion 
					ismot ⊢   ( 𝐺   ∈  𝑉   →  ( 𝐹   ∈  ( 𝐺  Ismt 𝐺  )  ↔  ( 𝐹  : 𝑃  –1-1 -onto → 𝑃   ∧  ∀ 𝑎   ∈  𝑃  ∀ 𝑏   ∈  𝑃  ( ( 𝐹  ‘ 𝑎  )  −   ( 𝐹  ‘ 𝑏  ) )  =  ( 𝑎   −   𝑏  ) ) ) )  
			
		 
		
				Proof 
				
					
						Step 
						Hyp 
						Ref 
						Expression 
					 
						
							1 
								
							 
							ismot.p ⊢  𝑃   =  ( Base ‘ 𝐺  )  
						
							2 
								
							 
							ismot.m ⊢   −    =  ( dist ‘ 𝐺  )  
						
							3 
								1  1  2  2 
							 
							isismt ⊢  ( ( 𝐺   ∈  𝑉   ∧  𝐺   ∈  𝑉  )  →  ( 𝐹   ∈  ( 𝐺  Ismt 𝐺  )  ↔  ( 𝐹  : 𝑃  –1-1 -onto → 𝑃   ∧  ∀ 𝑎   ∈  𝑃  ∀ 𝑏   ∈  𝑃  ( ( 𝐹  ‘ 𝑎  )  −   ( 𝐹  ‘ 𝑏  ) )  =  ( 𝑎   −   𝑏  ) ) ) )  
						
							4 
								3 
							 
							anidms ⊢  ( 𝐺   ∈  𝑉   →  ( 𝐹   ∈  ( 𝐺  Ismt 𝐺  )  ↔  ( 𝐹  : 𝑃  –1-1 -onto → 𝑃   ∧  ∀ 𝑎   ∈  𝑃  ∀ 𝑏   ∈  𝑃  ( ( 𝐹  ‘ 𝑎  )  −   ( 𝐹  ‘ 𝑏  ) )  =  ( 𝑎   −   𝑏  ) ) ) )