| Step | Hyp | Ref | Expression | 
						
							| 1 |  | frgpup.b | ⊢ 𝐵  =  ( Base ‘ 𝐻 ) | 
						
							| 2 |  | frgpup.n | ⊢ 𝑁  =  ( invg ‘ 𝐻 ) | 
						
							| 3 |  | frgpup.t | ⊢ 𝑇  =  ( 𝑦  ∈  𝐼 ,  𝑧  ∈  2o  ↦  if ( 𝑧  =  ∅ ,  ( 𝐹 ‘ 𝑦 ) ,  ( 𝑁 ‘ ( 𝐹 ‘ 𝑦 ) ) ) ) | 
						
							| 4 |  | frgpup.h | ⊢ ( 𝜑  →  𝐻  ∈  Grp ) | 
						
							| 5 |  | frgpup.i | ⊢ ( 𝜑  →  𝐼  ∈  𝑉 ) | 
						
							| 6 |  | frgpup.a | ⊢ ( 𝜑  →  𝐹 : 𝐼 ⟶ 𝐵 ) | 
						
							| 7 |  | frgpuptinv.m | ⊢ 𝑀  =  ( 𝑦  ∈  𝐼 ,  𝑧  ∈  2o  ↦  〈 𝑦 ,  ( 1o  ∖  𝑧 ) 〉 ) | 
						
							| 8 |  | elxp2 | ⊢ ( 𝐴  ∈  ( 𝐼  ×  2o )  ↔  ∃ 𝑎  ∈  𝐼 ∃ 𝑏  ∈  2o 𝐴  =  〈 𝑎 ,  𝑏 〉 ) | 
						
							| 9 | 7 | efgmval | ⊢ ( ( 𝑎  ∈  𝐼  ∧  𝑏  ∈  2o )  →  ( 𝑎 𝑀 𝑏 )  =  〈 𝑎 ,  ( 1o  ∖  𝑏 ) 〉 ) | 
						
							| 10 | 9 | adantl | ⊢ ( ( 𝜑  ∧  ( 𝑎  ∈  𝐼  ∧  𝑏  ∈  2o ) )  →  ( 𝑎 𝑀 𝑏 )  =  〈 𝑎 ,  ( 1o  ∖  𝑏 ) 〉 ) | 
						
							| 11 | 10 | fveq2d | ⊢ ( ( 𝜑  ∧  ( 𝑎  ∈  𝐼  ∧  𝑏  ∈  2o ) )  →  ( 𝑇 ‘ ( 𝑎 𝑀 𝑏 ) )  =  ( 𝑇 ‘ 〈 𝑎 ,  ( 1o  ∖  𝑏 ) 〉 ) ) | 
						
							| 12 |  | df-ov | ⊢ ( 𝑎 𝑇 ( 1o  ∖  𝑏 ) )  =  ( 𝑇 ‘ 〈 𝑎 ,  ( 1o  ∖  𝑏 ) 〉 ) | 
						
							| 13 | 11 12 | eqtr4di | ⊢ ( ( 𝜑  ∧  ( 𝑎  ∈  𝐼  ∧  𝑏  ∈  2o ) )  →  ( 𝑇 ‘ ( 𝑎 𝑀 𝑏 ) )  =  ( 𝑎 𝑇 ( 1o  ∖  𝑏 ) ) ) | 
						
							| 14 |  | elpri | ⊢ ( 𝑏  ∈  { ∅ ,  1o }  →  ( 𝑏  =  ∅  ∨  𝑏  =  1o ) ) | 
						
							| 15 |  | df2o3 | ⊢ 2o  =  { ∅ ,  1o } | 
						
							| 16 | 14 15 | eleq2s | ⊢ ( 𝑏  ∈  2o  →  ( 𝑏  =  ∅  ∨  𝑏  =  1o ) ) | 
						
							| 17 |  | simpr | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐼 )  →  𝑎  ∈  𝐼 ) | 
						
							| 18 |  | 1oex | ⊢ 1o  ∈  V | 
						
							| 19 | 18 | prid2 | ⊢ 1o  ∈  { ∅ ,  1o } | 
						
							| 20 | 19 15 | eleqtrri | ⊢ 1o  ∈  2o | 
						
							| 21 |  | 1n0 | ⊢ 1o  ≠  ∅ | 
						
							| 22 |  | neeq1 | ⊢ ( 𝑧  =  1o  →  ( 𝑧  ≠  ∅  ↔  1o  ≠  ∅ ) ) | 
						
							| 23 | 21 22 | mpbiri | ⊢ ( 𝑧  =  1o  →  𝑧  ≠  ∅ ) | 
						
							| 24 |  | ifnefalse | ⊢ ( 𝑧  ≠  ∅  →  if ( 𝑧  =  ∅ ,  ( 𝐹 ‘ 𝑦 ) ,  ( 𝑁 ‘ ( 𝐹 ‘ 𝑦 ) ) )  =  ( 𝑁 ‘ ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 25 | 23 24 | syl | ⊢ ( 𝑧  =  1o  →  if ( 𝑧  =  ∅ ,  ( 𝐹 ‘ 𝑦 ) ,  ( 𝑁 ‘ ( 𝐹 ‘ 𝑦 ) ) )  =  ( 𝑁 ‘ ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 26 |  | fveq2 | ⊢ ( 𝑦  =  𝑎  →  ( 𝐹 ‘ 𝑦 )  =  ( 𝐹 ‘ 𝑎 ) ) | 
						
							| 27 | 26 | fveq2d | ⊢ ( 𝑦  =  𝑎  →  ( 𝑁 ‘ ( 𝐹 ‘ 𝑦 ) )  =  ( 𝑁 ‘ ( 𝐹 ‘ 𝑎 ) ) ) | 
						
							| 28 | 25 27 | sylan9eqr | ⊢ ( ( 𝑦  =  𝑎  ∧  𝑧  =  1o )  →  if ( 𝑧  =  ∅ ,  ( 𝐹 ‘ 𝑦 ) ,  ( 𝑁 ‘ ( 𝐹 ‘ 𝑦 ) ) )  =  ( 𝑁 ‘ ( 𝐹 ‘ 𝑎 ) ) ) | 
						
							| 29 |  | fvex | ⊢ ( 𝑁 ‘ ( 𝐹 ‘ 𝑎 ) )  ∈  V | 
						
							| 30 | 28 3 29 | ovmpoa | ⊢ ( ( 𝑎  ∈  𝐼  ∧  1o  ∈  2o )  →  ( 𝑎 𝑇 1o )  =  ( 𝑁 ‘ ( 𝐹 ‘ 𝑎 ) ) ) | 
						
							| 31 | 17 20 30 | sylancl | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐼 )  →  ( 𝑎 𝑇 1o )  =  ( 𝑁 ‘ ( 𝐹 ‘ 𝑎 ) ) ) | 
						
							| 32 |  | 0ex | ⊢ ∅  ∈  V | 
						
							| 33 | 32 | prid1 | ⊢ ∅  ∈  { ∅ ,  1o } | 
						
							| 34 | 33 15 | eleqtrri | ⊢ ∅  ∈  2o | 
						
							| 35 |  | iftrue | ⊢ ( 𝑧  =  ∅  →  if ( 𝑧  =  ∅ ,  ( 𝐹 ‘ 𝑦 ) ,  ( 𝑁 ‘ ( 𝐹 ‘ 𝑦 ) ) )  =  ( 𝐹 ‘ 𝑦 ) ) | 
						
							| 36 | 35 26 | sylan9eqr | ⊢ ( ( 𝑦  =  𝑎  ∧  𝑧  =  ∅ )  →  if ( 𝑧  =  ∅ ,  ( 𝐹 ‘ 𝑦 ) ,  ( 𝑁 ‘ ( 𝐹 ‘ 𝑦 ) ) )  =  ( 𝐹 ‘ 𝑎 ) ) | 
						
							| 37 |  | fvex | ⊢ ( 𝐹 ‘ 𝑎 )  ∈  V | 
						
							| 38 | 36 3 37 | ovmpoa | ⊢ ( ( 𝑎  ∈  𝐼  ∧  ∅  ∈  2o )  →  ( 𝑎 𝑇 ∅ )  =  ( 𝐹 ‘ 𝑎 ) ) | 
						
							| 39 | 17 34 38 | sylancl | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐼 )  →  ( 𝑎 𝑇 ∅ )  =  ( 𝐹 ‘ 𝑎 ) ) | 
						
							| 40 | 39 | fveq2d | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐼 )  →  ( 𝑁 ‘ ( 𝑎 𝑇 ∅ ) )  =  ( 𝑁 ‘ ( 𝐹 ‘ 𝑎 ) ) ) | 
						
							| 41 | 31 40 | eqtr4d | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐼 )  →  ( 𝑎 𝑇 1o )  =  ( 𝑁 ‘ ( 𝑎 𝑇 ∅ ) ) ) | 
						
							| 42 |  | difeq2 | ⊢ ( 𝑏  =  ∅  →  ( 1o  ∖  𝑏 )  =  ( 1o  ∖  ∅ ) ) | 
						
							| 43 |  | dif0 | ⊢ ( 1o  ∖  ∅ )  =  1o | 
						
							| 44 | 42 43 | eqtrdi | ⊢ ( 𝑏  =  ∅  →  ( 1o  ∖  𝑏 )  =  1o ) | 
						
							| 45 | 44 | oveq2d | ⊢ ( 𝑏  =  ∅  →  ( 𝑎 𝑇 ( 1o  ∖  𝑏 ) )  =  ( 𝑎 𝑇 1o ) ) | 
						
							| 46 |  | oveq2 | ⊢ ( 𝑏  =  ∅  →  ( 𝑎 𝑇 𝑏 )  =  ( 𝑎 𝑇 ∅ ) ) | 
						
							| 47 | 46 | fveq2d | ⊢ ( 𝑏  =  ∅  →  ( 𝑁 ‘ ( 𝑎 𝑇 𝑏 ) )  =  ( 𝑁 ‘ ( 𝑎 𝑇 ∅ ) ) ) | 
						
							| 48 | 45 47 | eqeq12d | ⊢ ( 𝑏  =  ∅  →  ( ( 𝑎 𝑇 ( 1o  ∖  𝑏 ) )  =  ( 𝑁 ‘ ( 𝑎 𝑇 𝑏 ) )  ↔  ( 𝑎 𝑇 1o )  =  ( 𝑁 ‘ ( 𝑎 𝑇 ∅ ) ) ) ) | 
						
							| 49 | 41 48 | syl5ibrcom | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐼 )  →  ( 𝑏  =  ∅  →  ( 𝑎 𝑇 ( 1o  ∖  𝑏 ) )  =  ( 𝑁 ‘ ( 𝑎 𝑇 𝑏 ) ) ) ) | 
						
							| 50 | 41 | fveq2d | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐼 )  →  ( 𝑁 ‘ ( 𝑎 𝑇 1o ) )  =  ( 𝑁 ‘ ( 𝑁 ‘ ( 𝑎 𝑇 ∅ ) ) ) ) | 
						
							| 51 | 6 | ffvelcdmda | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐼 )  →  ( 𝐹 ‘ 𝑎 )  ∈  𝐵 ) | 
						
							| 52 | 39 51 | eqeltrd | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐼 )  →  ( 𝑎 𝑇 ∅ )  ∈  𝐵 ) | 
						
							| 53 | 1 2 | grpinvinv | ⊢ ( ( 𝐻  ∈  Grp  ∧  ( 𝑎 𝑇 ∅ )  ∈  𝐵 )  →  ( 𝑁 ‘ ( 𝑁 ‘ ( 𝑎 𝑇 ∅ ) ) )  =  ( 𝑎 𝑇 ∅ ) ) | 
						
							| 54 | 4 52 53 | syl2an2r | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐼 )  →  ( 𝑁 ‘ ( 𝑁 ‘ ( 𝑎 𝑇 ∅ ) ) )  =  ( 𝑎 𝑇 ∅ ) ) | 
						
							| 55 | 50 54 | eqtr2d | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐼 )  →  ( 𝑎 𝑇 ∅ )  =  ( 𝑁 ‘ ( 𝑎 𝑇 1o ) ) ) | 
						
							| 56 |  | difeq2 | ⊢ ( 𝑏  =  1o  →  ( 1o  ∖  𝑏 )  =  ( 1o  ∖  1o ) ) | 
						
							| 57 |  | difid | ⊢ ( 1o  ∖  1o )  =  ∅ | 
						
							| 58 | 56 57 | eqtrdi | ⊢ ( 𝑏  =  1o  →  ( 1o  ∖  𝑏 )  =  ∅ ) | 
						
							| 59 | 58 | oveq2d | ⊢ ( 𝑏  =  1o  →  ( 𝑎 𝑇 ( 1o  ∖  𝑏 ) )  =  ( 𝑎 𝑇 ∅ ) ) | 
						
							| 60 |  | oveq2 | ⊢ ( 𝑏  =  1o  →  ( 𝑎 𝑇 𝑏 )  =  ( 𝑎 𝑇 1o ) ) | 
						
							| 61 | 60 | fveq2d | ⊢ ( 𝑏  =  1o  →  ( 𝑁 ‘ ( 𝑎 𝑇 𝑏 ) )  =  ( 𝑁 ‘ ( 𝑎 𝑇 1o ) ) ) | 
						
							| 62 | 59 61 | eqeq12d | ⊢ ( 𝑏  =  1o  →  ( ( 𝑎 𝑇 ( 1o  ∖  𝑏 ) )  =  ( 𝑁 ‘ ( 𝑎 𝑇 𝑏 ) )  ↔  ( 𝑎 𝑇 ∅ )  =  ( 𝑁 ‘ ( 𝑎 𝑇 1o ) ) ) ) | 
						
							| 63 | 55 62 | syl5ibrcom | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐼 )  →  ( 𝑏  =  1o  →  ( 𝑎 𝑇 ( 1o  ∖  𝑏 ) )  =  ( 𝑁 ‘ ( 𝑎 𝑇 𝑏 ) ) ) ) | 
						
							| 64 | 49 63 | jaod | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐼 )  →  ( ( 𝑏  =  ∅  ∨  𝑏  =  1o )  →  ( 𝑎 𝑇 ( 1o  ∖  𝑏 ) )  =  ( 𝑁 ‘ ( 𝑎 𝑇 𝑏 ) ) ) ) | 
						
							| 65 | 16 64 | syl5 | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐼 )  →  ( 𝑏  ∈  2o  →  ( 𝑎 𝑇 ( 1o  ∖  𝑏 ) )  =  ( 𝑁 ‘ ( 𝑎 𝑇 𝑏 ) ) ) ) | 
						
							| 66 | 65 | impr | ⊢ ( ( 𝜑  ∧  ( 𝑎  ∈  𝐼  ∧  𝑏  ∈  2o ) )  →  ( 𝑎 𝑇 ( 1o  ∖  𝑏 ) )  =  ( 𝑁 ‘ ( 𝑎 𝑇 𝑏 ) ) ) | 
						
							| 67 | 13 66 | eqtrd | ⊢ ( ( 𝜑  ∧  ( 𝑎  ∈  𝐼  ∧  𝑏  ∈  2o ) )  →  ( 𝑇 ‘ ( 𝑎 𝑀 𝑏 ) )  =  ( 𝑁 ‘ ( 𝑎 𝑇 𝑏 ) ) ) | 
						
							| 68 |  | fveq2 | ⊢ ( 𝐴  =  〈 𝑎 ,  𝑏 〉  →  ( 𝑀 ‘ 𝐴 )  =  ( 𝑀 ‘ 〈 𝑎 ,  𝑏 〉 ) ) | 
						
							| 69 |  | df-ov | ⊢ ( 𝑎 𝑀 𝑏 )  =  ( 𝑀 ‘ 〈 𝑎 ,  𝑏 〉 ) | 
						
							| 70 | 68 69 | eqtr4di | ⊢ ( 𝐴  =  〈 𝑎 ,  𝑏 〉  →  ( 𝑀 ‘ 𝐴 )  =  ( 𝑎 𝑀 𝑏 ) ) | 
						
							| 71 | 70 | fveq2d | ⊢ ( 𝐴  =  〈 𝑎 ,  𝑏 〉  →  ( 𝑇 ‘ ( 𝑀 ‘ 𝐴 ) )  =  ( 𝑇 ‘ ( 𝑎 𝑀 𝑏 ) ) ) | 
						
							| 72 |  | fveq2 | ⊢ ( 𝐴  =  〈 𝑎 ,  𝑏 〉  →  ( 𝑇 ‘ 𝐴 )  =  ( 𝑇 ‘ 〈 𝑎 ,  𝑏 〉 ) ) | 
						
							| 73 |  | df-ov | ⊢ ( 𝑎 𝑇 𝑏 )  =  ( 𝑇 ‘ 〈 𝑎 ,  𝑏 〉 ) | 
						
							| 74 | 72 73 | eqtr4di | ⊢ ( 𝐴  =  〈 𝑎 ,  𝑏 〉  →  ( 𝑇 ‘ 𝐴 )  =  ( 𝑎 𝑇 𝑏 ) ) | 
						
							| 75 | 74 | fveq2d | ⊢ ( 𝐴  =  〈 𝑎 ,  𝑏 〉  →  ( 𝑁 ‘ ( 𝑇 ‘ 𝐴 ) )  =  ( 𝑁 ‘ ( 𝑎 𝑇 𝑏 ) ) ) | 
						
							| 76 | 71 75 | eqeq12d | ⊢ ( 𝐴  =  〈 𝑎 ,  𝑏 〉  →  ( ( 𝑇 ‘ ( 𝑀 ‘ 𝐴 ) )  =  ( 𝑁 ‘ ( 𝑇 ‘ 𝐴 ) )  ↔  ( 𝑇 ‘ ( 𝑎 𝑀 𝑏 ) )  =  ( 𝑁 ‘ ( 𝑎 𝑇 𝑏 ) ) ) ) | 
						
							| 77 | 67 76 | syl5ibrcom | ⊢ ( ( 𝜑  ∧  ( 𝑎  ∈  𝐼  ∧  𝑏  ∈  2o ) )  →  ( 𝐴  =  〈 𝑎 ,  𝑏 〉  →  ( 𝑇 ‘ ( 𝑀 ‘ 𝐴 ) )  =  ( 𝑁 ‘ ( 𝑇 ‘ 𝐴 ) ) ) ) | 
						
							| 78 | 77 | rexlimdvva | ⊢ ( 𝜑  →  ( ∃ 𝑎  ∈  𝐼 ∃ 𝑏  ∈  2o 𝐴  =  〈 𝑎 ,  𝑏 〉  →  ( 𝑇 ‘ ( 𝑀 ‘ 𝐴 ) )  =  ( 𝑁 ‘ ( 𝑇 ‘ 𝐴 ) ) ) ) | 
						
							| 79 | 8 78 | biimtrid | ⊢ ( 𝜑  →  ( 𝐴  ∈  ( 𝐼  ×  2o )  →  ( 𝑇 ‘ ( 𝑀 ‘ 𝐴 ) )  =  ( 𝑁 ‘ ( 𝑇 ‘ 𝐴 ) ) ) ) | 
						
							| 80 | 79 | imp | ⊢ ( ( 𝜑  ∧  𝐴  ∈  ( 𝐼  ×  2o ) )  →  ( 𝑇 ‘ ( 𝑀 ‘ 𝐴 ) )  =  ( 𝑁 ‘ ( 𝑇 ‘ 𝐴 ) ) ) |