| Step | Hyp | Ref | Expression | 
						
							| 1 |  | psgnval.g | ⊢ 𝐺  =  ( SymGrp ‘ 𝐷 ) | 
						
							| 2 |  | psgnval.t | ⊢ 𝑇  =  ran  ( pmTrsp ‘ 𝐷 ) | 
						
							| 3 |  | psgnval.n | ⊢ 𝑁  =  ( pmSgn ‘ 𝐷 ) | 
						
							| 4 |  | eqid | ⊢ ( Base ‘ 𝐺 )  =  ( Base ‘ 𝐺 ) | 
						
							| 5 |  | eqid | ⊢ { 𝑝  ∈  ( Base ‘ 𝐺 )  ∣  dom  ( 𝑝  ∖   I  )  ∈  Fin }  =  { 𝑝  ∈  ( Base ‘ 𝐺 )  ∣  dom  ( 𝑝  ∖   I  )  ∈  Fin } | 
						
							| 6 | 1 4 5 3 | psgnfn | ⊢ 𝑁  Fn  { 𝑝  ∈  ( Base ‘ 𝐺 )  ∣  dom  ( 𝑝  ∖   I  )  ∈  Fin } | 
						
							| 7 | 6 | fndmi | ⊢ dom  𝑁  =  { 𝑝  ∈  ( Base ‘ 𝐺 )  ∣  dom  ( 𝑝  ∖   I  )  ∈  Fin } | 
						
							| 8 |  | eqid | ⊢ ( mrCls ‘ ( SubMnd ‘ 𝐺 ) )  =  ( mrCls ‘ ( SubMnd ‘ 𝐺 ) ) | 
						
							| 9 | 2 1 4 8 | symggen | ⊢ ( 𝐷  ∈  𝑉  →  ( ( mrCls ‘ ( SubMnd ‘ 𝐺 ) ) ‘ 𝑇 )  =  { 𝑝  ∈  ( Base ‘ 𝐺 )  ∣  dom  ( 𝑝  ∖   I  )  ∈  Fin } ) | 
						
							| 10 | 1 | symggrp | ⊢ ( 𝐷  ∈  𝑉  →  𝐺  ∈  Grp ) | 
						
							| 11 | 10 | grpmndd | ⊢ ( 𝐷  ∈  𝑉  →  𝐺  ∈  Mnd ) | 
						
							| 12 | 2 1 4 | symgtrf | ⊢ 𝑇  ⊆  ( Base ‘ 𝐺 ) | 
						
							| 13 | 4 8 | gsumwspan | ⊢ ( ( 𝐺  ∈  Mnd  ∧  𝑇  ⊆  ( Base ‘ 𝐺 ) )  →  ( ( mrCls ‘ ( SubMnd ‘ 𝐺 ) ) ‘ 𝑇 )  =  ran  ( 𝑤  ∈  Word  𝑇  ↦  ( 𝐺  Σg  𝑤 ) ) ) | 
						
							| 14 | 11 12 13 | sylancl | ⊢ ( 𝐷  ∈  𝑉  →  ( ( mrCls ‘ ( SubMnd ‘ 𝐺 ) ) ‘ 𝑇 )  =  ran  ( 𝑤  ∈  Word  𝑇  ↦  ( 𝐺  Σg  𝑤 ) ) ) | 
						
							| 15 | 9 14 | eqtr3d | ⊢ ( 𝐷  ∈  𝑉  →  { 𝑝  ∈  ( Base ‘ 𝐺 )  ∣  dom  ( 𝑝  ∖   I  )  ∈  Fin }  =  ran  ( 𝑤  ∈  Word  𝑇  ↦  ( 𝐺  Σg  𝑤 ) ) ) | 
						
							| 16 | 7 15 | eqtrid | ⊢ ( 𝐷  ∈  𝑉  →  dom  𝑁  =  ran  ( 𝑤  ∈  Word  𝑇  ↦  ( 𝐺  Σg  𝑤 ) ) ) | 
						
							| 17 | 16 | eleq2d | ⊢ ( 𝐷  ∈  𝑉  →  ( 𝑃  ∈  dom  𝑁  ↔  𝑃  ∈  ran  ( 𝑤  ∈  Word  𝑇  ↦  ( 𝐺  Σg  𝑤 ) ) ) ) | 
						
							| 18 |  | eqid | ⊢ ( 𝑤  ∈  Word  𝑇  ↦  ( 𝐺  Σg  𝑤 ) )  =  ( 𝑤  ∈  Word  𝑇  ↦  ( 𝐺  Σg  𝑤 ) ) | 
						
							| 19 |  | ovex | ⊢ ( 𝐺  Σg  𝑤 )  ∈  V | 
						
							| 20 | 18 19 | elrnmpti | ⊢ ( 𝑃  ∈  ran  ( 𝑤  ∈  Word  𝑇  ↦  ( 𝐺  Σg  𝑤 ) )  ↔  ∃ 𝑤  ∈  Word  𝑇 𝑃  =  ( 𝐺  Σg  𝑤 ) ) | 
						
							| 21 | 17 20 | bitrdi | ⊢ ( 𝐷  ∈  𝑉  →  ( 𝑃  ∈  dom  𝑁  ↔  ∃ 𝑤  ∈  Word  𝑇 𝑃  =  ( 𝐺  Σg  𝑤 ) ) ) |