| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mndind.ch | ⊢ ( 𝑥  =  𝑦  →  ( 𝜓  ↔  𝜒 ) ) | 
						
							| 2 |  | mndind.th | ⊢ ( 𝑥  =  ( 𝑦  +  𝑧 )  →  ( 𝜓  ↔  𝜃 ) ) | 
						
							| 3 |  | mndind.ta | ⊢ ( 𝑥  =   0   →  ( 𝜓  ↔  𝜏 ) ) | 
						
							| 4 |  | mndind.et | ⊢ ( 𝑥  =  𝐴  →  ( 𝜓  ↔  𝜂 ) ) | 
						
							| 5 |  | mndind.0g | ⊢  0   =  ( 0g ‘ 𝑀 ) | 
						
							| 6 |  | mndind.pg | ⊢  +   =  ( +g ‘ 𝑀 ) | 
						
							| 7 |  | mndind.b | ⊢ 𝐵  =  ( Base ‘ 𝑀 ) | 
						
							| 8 |  | mndind.m | ⊢ ( 𝜑  →  𝑀  ∈  Mnd ) | 
						
							| 9 |  | mndind.g | ⊢ ( 𝜑  →  𝐺  ⊆  𝐵 ) | 
						
							| 10 |  | mndind.k | ⊢ ( 𝜑  →  𝐵  =  ( ( mrCls ‘ ( SubMnd ‘ 𝑀 ) ) ‘ 𝐺 ) ) | 
						
							| 11 |  | mndind.i1 | ⊢ ( 𝜑  →  𝜏 ) | 
						
							| 12 |  | mndind.i2 | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  𝐵  ∧  𝑧  ∈  𝐺 )  ∧  𝜒 )  →  𝜃 ) | 
						
							| 13 |  | mndind.a | ⊢ ( 𝜑  →  𝐴  ∈  𝐵 ) | 
						
							| 14 | 7 5 | mndidcl | ⊢ ( 𝑀  ∈  Mnd  →   0   ∈  𝐵 ) | 
						
							| 15 | 8 14 | syl | ⊢ ( 𝜑  →   0   ∈  𝐵 ) | 
						
							| 16 | 3 | sbcieg | ⊢ (  0   ∈  𝐵  →  ( [  0   /  𝑥 ] 𝜓  ↔  𝜏 ) ) | 
						
							| 17 | 15 16 | syl | ⊢ ( 𝜑  →  ( [  0   /  𝑥 ] 𝜓  ↔  𝜏 ) ) | 
						
							| 18 | 11 17 | mpbird | ⊢ ( 𝜑  →  [  0   /  𝑥 ] 𝜓 ) | 
						
							| 19 |  | dfsbcq | ⊢ ( 𝑎  =   0   →  ( [ 𝑎  /  𝑥 ] 𝜓  ↔  [  0   /  𝑥 ] 𝜓 ) ) | 
						
							| 20 |  | oveq1 | ⊢ ( 𝑎  =   0   →  ( 𝑎  +  𝐴 )  =  (  0   +  𝐴 ) ) | 
						
							| 21 | 20 | sbceq1d | ⊢ ( 𝑎  =   0   →  ( [ ( 𝑎  +  𝐴 )  /  𝑥 ] 𝜓  ↔  [ (  0   +  𝐴 )  /  𝑥 ] 𝜓 ) ) | 
						
							| 22 | 19 21 | imbi12d | ⊢ ( 𝑎  =   0   →  ( ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝐴 )  /  𝑥 ] 𝜓 )  ↔  ( [  0   /  𝑥 ] 𝜓  →  [ (  0   +  𝐴 )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 23 | 7 | submacs | ⊢ ( 𝑀  ∈  Mnd  →  ( SubMnd ‘ 𝑀 )  ∈  ( ACS ‘ 𝐵 ) ) | 
						
							| 24 | 8 23 | syl | ⊢ ( 𝜑  →  ( SubMnd ‘ 𝑀 )  ∈  ( ACS ‘ 𝐵 ) ) | 
						
							| 25 | 24 | acsmred | ⊢ ( 𝜑  →  ( SubMnd ‘ 𝑀 )  ∈  ( Moore ‘ 𝐵 ) ) | 
						
							| 26 |  | eleq1w | ⊢ ( 𝑦  =  𝑎  →  ( 𝑦  ∈  𝐵  ↔  𝑎  ∈  𝐵 ) ) | 
						
							| 27 | 26 | anbi2d | ⊢ ( 𝑦  =  𝑎  →  ( ( ( 𝜑  ∧  𝑏  ∈  𝐺 )  ∧  𝑦  ∈  𝐵 )  ↔  ( ( 𝜑  ∧  𝑏  ∈  𝐺 )  ∧  𝑎  ∈  𝐵 ) ) ) | 
						
							| 28 |  | vex | ⊢ 𝑦  ∈  V | 
						
							| 29 | 28 1 | sbcie | ⊢ ( [ 𝑦  /  𝑥 ] 𝜓  ↔  𝜒 ) | 
						
							| 30 |  | dfsbcq | ⊢ ( 𝑦  =  𝑎  →  ( [ 𝑦  /  𝑥 ] 𝜓  ↔  [ 𝑎  /  𝑥 ] 𝜓 ) ) | 
						
							| 31 | 29 30 | bitr3id | ⊢ ( 𝑦  =  𝑎  →  ( 𝜒  ↔  [ 𝑎  /  𝑥 ] 𝜓 ) ) | 
						
							| 32 |  | oveq1 | ⊢ ( 𝑦  =  𝑎  →  ( 𝑦  +  𝑏 )  =  ( 𝑎  +  𝑏 ) ) | 
						
							| 33 | 32 | sbceq1d | ⊢ ( 𝑦  =  𝑎  →  ( [ ( 𝑦  +  𝑏 )  /  𝑥 ] 𝜓  ↔  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 ) ) | 
						
							| 34 | 31 33 | imbi12d | ⊢ ( 𝑦  =  𝑎  →  ( ( 𝜒  →  [ ( 𝑦  +  𝑏 )  /  𝑥 ] 𝜓 )  ↔  ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 35 | 27 34 | imbi12d | ⊢ ( 𝑦  =  𝑎  →  ( ( ( ( 𝜑  ∧  𝑏  ∈  𝐺 )  ∧  𝑦  ∈  𝐵 )  →  ( 𝜒  →  [ ( 𝑦  +  𝑏 )  /  𝑥 ] 𝜓 ) )  ↔  ( ( ( 𝜑  ∧  𝑏  ∈  𝐺 )  ∧  𝑎  ∈  𝐵 )  →  ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 ) ) ) ) | 
						
							| 36 |  | eleq1w | ⊢ ( 𝑧  =  𝑏  →  ( 𝑧  ∈  𝐺  ↔  𝑏  ∈  𝐺 ) ) | 
						
							| 37 | 36 | anbi2d | ⊢ ( 𝑧  =  𝑏  →  ( ( 𝜑  ∧  𝑧  ∈  𝐺 )  ↔  ( 𝜑  ∧  𝑏  ∈  𝐺 ) ) ) | 
						
							| 38 | 37 | anbi1d | ⊢ ( 𝑧  =  𝑏  →  ( ( ( 𝜑  ∧  𝑧  ∈  𝐺 )  ∧  𝑦  ∈  𝐵 )  ↔  ( ( 𝜑  ∧  𝑏  ∈  𝐺 )  ∧  𝑦  ∈  𝐵 ) ) ) | 
						
							| 39 |  | ovex | ⊢ ( 𝑦  +  𝑧 )  ∈  V | 
						
							| 40 | 39 2 | sbcie | ⊢ ( [ ( 𝑦  +  𝑧 )  /  𝑥 ] 𝜓  ↔  𝜃 ) | 
						
							| 41 |  | oveq2 | ⊢ ( 𝑧  =  𝑏  →  ( 𝑦  +  𝑧 )  =  ( 𝑦  +  𝑏 ) ) | 
						
							| 42 | 41 | sbceq1d | ⊢ ( 𝑧  =  𝑏  →  ( [ ( 𝑦  +  𝑧 )  /  𝑥 ] 𝜓  ↔  [ ( 𝑦  +  𝑏 )  /  𝑥 ] 𝜓 ) ) | 
						
							| 43 | 40 42 | bitr3id | ⊢ ( 𝑧  =  𝑏  →  ( 𝜃  ↔  [ ( 𝑦  +  𝑏 )  /  𝑥 ] 𝜓 ) ) | 
						
							| 44 | 43 | imbi2d | ⊢ ( 𝑧  =  𝑏  →  ( ( 𝜒  →  𝜃 )  ↔  ( 𝜒  →  [ ( 𝑦  +  𝑏 )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 45 | 38 44 | imbi12d | ⊢ ( 𝑧  =  𝑏  →  ( ( ( ( 𝜑  ∧  𝑧  ∈  𝐺 )  ∧  𝑦  ∈  𝐵 )  →  ( 𝜒  →  𝜃 ) )  ↔  ( ( ( 𝜑  ∧  𝑏  ∈  𝐺 )  ∧  𝑦  ∈  𝐵 )  →  ( 𝜒  →  [ ( 𝑦  +  𝑏 )  /  𝑥 ] 𝜓 ) ) ) ) | 
						
							| 46 | 12 | ex | ⊢ ( ( 𝜑  ∧  𝑦  ∈  𝐵  ∧  𝑧  ∈  𝐺 )  →  ( 𝜒  →  𝜃 ) ) | 
						
							| 47 | 46 | 3expa | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  𝐵 )  ∧  𝑧  ∈  𝐺 )  →  ( 𝜒  →  𝜃 ) ) | 
						
							| 48 | 47 | an32s | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  𝐺 )  ∧  𝑦  ∈  𝐵 )  →  ( 𝜒  →  𝜃 ) ) | 
						
							| 49 | 45 48 | chvarvv | ⊢ ( ( ( 𝜑  ∧  𝑏  ∈  𝐺 )  ∧  𝑦  ∈  𝐵 )  →  ( 𝜒  →  [ ( 𝑦  +  𝑏 )  /  𝑥 ] 𝜓 ) ) | 
						
							| 50 | 35 49 | chvarvv | ⊢ ( ( ( 𝜑  ∧  𝑏  ∈  𝐺 )  ∧  𝑎  ∈  𝐵 )  →  ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 ) ) | 
						
							| 51 | 50 | ralrimiva | ⊢ ( ( 𝜑  ∧  𝑏  ∈  𝐺 )  →  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 ) ) | 
						
							| 52 | 9 51 | ssrabdv | ⊢ ( 𝜑  →  𝐺  ⊆  { 𝑏  ∈  𝐵  ∣  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 ) } ) | 
						
							| 53 | 7 6 5 | mndrid | ⊢ ( ( 𝑀  ∈  Mnd  ∧  𝑎  ∈  𝐵 )  →  ( 𝑎  +   0  )  =  𝑎 ) | 
						
							| 54 | 8 53 | sylan | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐵 )  →  ( 𝑎  +   0  )  =  𝑎 ) | 
						
							| 55 | 54 | sbceq1d | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐵 )  →  ( [ ( 𝑎  +   0  )  /  𝑥 ] 𝜓  ↔  [ 𝑎  /  𝑥 ] 𝜓 ) ) | 
						
							| 56 | 55 | biimprd | ⊢ ( ( 𝜑  ∧  𝑎  ∈  𝐵 )  →  ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +   0  )  /  𝑥 ] 𝜓 ) ) | 
						
							| 57 | 56 | ralrimiva | ⊢ ( 𝜑  →  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +   0  )  /  𝑥 ] 𝜓 ) ) | 
						
							| 58 |  | simprrl | ⊢ ( ( 𝜑  ∧  ( ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 )  ∧  ( ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑐 )  /  𝑥 ] 𝜓 )  ∧  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑑 )  /  𝑥 ] 𝜓 ) ) ) )  →  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑐 )  /  𝑥 ] 𝜓 ) ) | 
						
							| 59 | 8 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 ) )  ∧  𝑏  ∈  𝐵 )  →  𝑀  ∈  Mnd ) | 
						
							| 60 |  | simpr | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 ) )  ∧  𝑏  ∈  𝐵 )  →  𝑏  ∈  𝐵 ) | 
						
							| 61 |  | simplrl | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 ) )  ∧  𝑏  ∈  𝐵 )  →  𝑐  ∈  𝐵 ) | 
						
							| 62 | 7 6 | mndcl | ⊢ ( ( 𝑀  ∈  Mnd  ∧  𝑏  ∈  𝐵  ∧  𝑐  ∈  𝐵 )  →  ( 𝑏  +  𝑐 )  ∈  𝐵 ) | 
						
							| 63 | 59 60 61 62 | syl3anc | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 ) )  ∧  𝑏  ∈  𝐵 )  →  ( 𝑏  +  𝑐 )  ∈  𝐵 ) | 
						
							| 64 |  | simpr | ⊢ ( ( ( ( 𝜑  ∧  ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 ) )  ∧  𝑏  ∈  𝐵 )  ∧  𝑎  =  ( 𝑏  +  𝑐 ) )  →  𝑎  =  ( 𝑏  +  𝑐 ) ) | 
						
							| 65 | 64 | sbceq1d | ⊢ ( ( ( ( 𝜑  ∧  ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 ) )  ∧  𝑏  ∈  𝐵 )  ∧  𝑎  =  ( 𝑏  +  𝑐 ) )  →  ( [ 𝑎  /  𝑥 ] 𝜓  ↔  [ ( 𝑏  +  𝑐 )  /  𝑥 ] 𝜓 ) ) | 
						
							| 66 |  | oveq1 | ⊢ ( 𝑎  =  ( 𝑏  +  𝑐 )  →  ( 𝑎  +  𝑑 )  =  ( ( 𝑏  +  𝑐 )  +  𝑑 ) ) | 
						
							| 67 |  | simplrr | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 ) )  ∧  𝑏  ∈  𝐵 )  →  𝑑  ∈  𝐵 ) | 
						
							| 68 | 7 6 | mndass | ⊢ ( ( 𝑀  ∈  Mnd  ∧  ( 𝑏  ∈  𝐵  ∧  𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 ) )  →  ( ( 𝑏  +  𝑐 )  +  𝑑 )  =  ( 𝑏  +  ( 𝑐  +  𝑑 ) ) ) | 
						
							| 69 | 59 60 61 67 68 | syl13anc | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 ) )  ∧  𝑏  ∈  𝐵 )  →  ( ( 𝑏  +  𝑐 )  +  𝑑 )  =  ( 𝑏  +  ( 𝑐  +  𝑑 ) ) ) | 
						
							| 70 | 66 69 | sylan9eqr | ⊢ ( ( ( ( 𝜑  ∧  ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 ) )  ∧  𝑏  ∈  𝐵 )  ∧  𝑎  =  ( 𝑏  +  𝑐 ) )  →  ( 𝑎  +  𝑑 )  =  ( 𝑏  +  ( 𝑐  +  𝑑 ) ) ) | 
						
							| 71 | 70 | sbceq1d | ⊢ ( ( ( ( 𝜑  ∧  ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 ) )  ∧  𝑏  ∈  𝐵 )  ∧  𝑎  =  ( 𝑏  +  𝑐 ) )  →  ( [ ( 𝑎  +  𝑑 )  /  𝑥 ] 𝜓  ↔  [ ( 𝑏  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 ) ) | 
						
							| 72 | 65 71 | imbi12d | ⊢ ( ( ( ( 𝜑  ∧  ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 ) )  ∧  𝑏  ∈  𝐵 )  ∧  𝑎  =  ( 𝑏  +  𝑐 ) )  →  ( ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑑 )  /  𝑥 ] 𝜓 )  ↔  ( [ ( 𝑏  +  𝑐 )  /  𝑥 ] 𝜓  →  [ ( 𝑏  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 73 | 63 72 | rspcdv | ⊢ ( ( ( 𝜑  ∧  ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 ) )  ∧  𝑏  ∈  𝐵 )  →  ( ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑑 )  /  𝑥 ] 𝜓 )  →  ( [ ( 𝑏  +  𝑐 )  /  𝑥 ] 𝜓  →  [ ( 𝑏  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 74 | 73 | ralrimdva | ⊢ ( ( 𝜑  ∧  ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 ) )  →  ( ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑑 )  /  𝑥 ] 𝜓 )  →  ∀ 𝑏  ∈  𝐵 ( [ ( 𝑏  +  𝑐 )  /  𝑥 ] 𝜓  →  [ ( 𝑏  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 75 | 74 | impr | ⊢ ( ( 𝜑  ∧  ( ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 )  ∧  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑑 )  /  𝑥 ] 𝜓 ) ) )  →  ∀ 𝑏  ∈  𝐵 ( [ ( 𝑏  +  𝑐 )  /  𝑥 ] 𝜓  →  [ ( 𝑏  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 ) ) | 
						
							| 76 |  | oveq1 | ⊢ ( 𝑏  =  𝑎  →  ( 𝑏  +  𝑐 )  =  ( 𝑎  +  𝑐 ) ) | 
						
							| 77 | 76 | sbceq1d | ⊢ ( 𝑏  =  𝑎  →  ( [ ( 𝑏  +  𝑐 )  /  𝑥 ] 𝜓  ↔  [ ( 𝑎  +  𝑐 )  /  𝑥 ] 𝜓 ) ) | 
						
							| 78 |  | oveq1 | ⊢ ( 𝑏  =  𝑎  →  ( 𝑏  +  ( 𝑐  +  𝑑 ) )  =  ( 𝑎  +  ( 𝑐  +  𝑑 ) ) ) | 
						
							| 79 | 78 | sbceq1d | ⊢ ( 𝑏  =  𝑎  →  ( [ ( 𝑏  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓  ↔  [ ( 𝑎  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 ) ) | 
						
							| 80 | 77 79 | imbi12d | ⊢ ( 𝑏  =  𝑎  →  ( ( [ ( 𝑏  +  𝑐 )  /  𝑥 ] 𝜓  →  [ ( 𝑏  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 )  ↔  ( [ ( 𝑎  +  𝑐 )  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 81 | 80 | cbvralvw | ⊢ ( ∀ 𝑏  ∈  𝐵 ( [ ( 𝑏  +  𝑐 )  /  𝑥 ] 𝜓  →  [ ( 𝑏  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 )  ↔  ∀ 𝑎  ∈  𝐵 ( [ ( 𝑎  +  𝑐 )  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 ) ) | 
						
							| 82 | 75 81 | sylib | ⊢ ( ( 𝜑  ∧  ( ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 )  ∧  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑑 )  /  𝑥 ] 𝜓 ) ) )  →  ∀ 𝑎  ∈  𝐵 ( [ ( 𝑎  +  𝑐 )  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 ) ) | 
						
							| 83 | 82 | adantrrl | ⊢ ( ( 𝜑  ∧  ( ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 )  ∧  ( ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑐 )  /  𝑥 ] 𝜓 )  ∧  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑑 )  /  𝑥 ] 𝜓 ) ) ) )  →  ∀ 𝑎  ∈  𝐵 ( [ ( 𝑎  +  𝑐 )  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 ) ) | 
						
							| 84 |  | imim1 | ⊢ ( ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑐 )  /  𝑥 ] 𝜓 )  →  ( ( [ ( 𝑎  +  𝑐 )  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 )  →  ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 85 | 84 | ral2imi | ⊢ ( ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑐 )  /  𝑥 ] 𝜓 )  →  ( ∀ 𝑎  ∈  𝐵 ( [ ( 𝑎  +  𝑐 )  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 )  →  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 86 | 58 83 85 | sylc | ⊢ ( ( 𝜑  ∧  ( ( 𝑐  ∈  𝐵  ∧  𝑑  ∈  𝐵 )  ∧  ( ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑐 )  /  𝑥 ] 𝜓 )  ∧  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑑 )  /  𝑥 ] 𝜓 ) ) ) )  →  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 ) ) | 
						
							| 87 |  | oveq2 | ⊢ ( 𝑏  =   0   →  ( 𝑎  +  𝑏 )  =  ( 𝑎  +   0  ) ) | 
						
							| 88 | 87 | sbceq1d | ⊢ ( 𝑏  =   0   →  ( [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓  ↔  [ ( 𝑎  +   0  )  /  𝑥 ] 𝜓 ) ) | 
						
							| 89 | 88 | imbi2d | ⊢ ( 𝑏  =   0   →  ( ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 )  ↔  ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +   0  )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 90 | 89 | ralbidv | ⊢ ( 𝑏  =   0   →  ( ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 )  ↔  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +   0  )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 91 |  | oveq2 | ⊢ ( 𝑏  =  𝑐  →  ( 𝑎  +  𝑏 )  =  ( 𝑎  +  𝑐 ) ) | 
						
							| 92 | 91 | sbceq1d | ⊢ ( 𝑏  =  𝑐  →  ( [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓  ↔  [ ( 𝑎  +  𝑐 )  /  𝑥 ] 𝜓 ) ) | 
						
							| 93 | 92 | imbi2d | ⊢ ( 𝑏  =  𝑐  →  ( ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 )  ↔  ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑐 )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 94 | 93 | ralbidv | ⊢ ( 𝑏  =  𝑐  →  ( ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 )  ↔  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑐 )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 95 |  | oveq2 | ⊢ ( 𝑏  =  𝑑  →  ( 𝑎  +  𝑏 )  =  ( 𝑎  +  𝑑 ) ) | 
						
							| 96 | 95 | sbceq1d | ⊢ ( 𝑏  =  𝑑  →  ( [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓  ↔  [ ( 𝑎  +  𝑑 )  /  𝑥 ] 𝜓 ) ) | 
						
							| 97 | 96 | imbi2d | ⊢ ( 𝑏  =  𝑑  →  ( ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 )  ↔  ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑑 )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 98 | 97 | ralbidv | ⊢ ( 𝑏  =  𝑑  →  ( ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 )  ↔  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑑 )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 99 |  | oveq2 | ⊢ ( 𝑏  =  ( 𝑐  +  𝑑 )  →  ( 𝑎  +  𝑏 )  =  ( 𝑎  +  ( 𝑐  +  𝑑 ) ) ) | 
						
							| 100 | 99 | sbceq1d | ⊢ ( 𝑏  =  ( 𝑐  +  𝑑 )  →  ( [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓  ↔  [ ( 𝑎  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 ) ) | 
						
							| 101 | 100 | imbi2d | ⊢ ( 𝑏  =  ( 𝑐  +  𝑑 )  →  ( ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 )  ↔  ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 102 | 101 | ralbidv | ⊢ ( 𝑏  =  ( 𝑐  +  𝑑 )  →  ( ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 )  ↔  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  ( 𝑐  +  𝑑 ) )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 103 | 7 6 5 8 57 86 90 94 98 102 | issubmd | ⊢ ( 𝜑  →  { 𝑏  ∈  𝐵  ∣  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 ) }  ∈  ( SubMnd ‘ 𝑀 ) ) | 
						
							| 104 |  | eqid | ⊢ ( mrCls ‘ ( SubMnd ‘ 𝑀 ) )  =  ( mrCls ‘ ( SubMnd ‘ 𝑀 ) ) | 
						
							| 105 | 104 | mrcsscl | ⊢ ( ( ( SubMnd ‘ 𝑀 )  ∈  ( Moore ‘ 𝐵 )  ∧  𝐺  ⊆  { 𝑏  ∈  𝐵  ∣  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 ) }  ∧  { 𝑏  ∈  𝐵  ∣  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 ) }  ∈  ( SubMnd ‘ 𝑀 ) )  →  ( ( mrCls ‘ ( SubMnd ‘ 𝑀 ) ) ‘ 𝐺 )  ⊆  { 𝑏  ∈  𝐵  ∣  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 ) } ) | 
						
							| 106 | 25 52 103 105 | syl3anc | ⊢ ( 𝜑  →  ( ( mrCls ‘ ( SubMnd ‘ 𝑀 ) ) ‘ 𝐺 )  ⊆  { 𝑏  ∈  𝐵  ∣  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 ) } ) | 
						
							| 107 | 10 106 | eqsstrd | ⊢ ( 𝜑  →  𝐵  ⊆  { 𝑏  ∈  𝐵  ∣  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 ) } ) | 
						
							| 108 | 107 13 | sseldd | ⊢ ( 𝜑  →  𝐴  ∈  { 𝑏  ∈  𝐵  ∣  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 ) } ) | 
						
							| 109 |  | oveq2 | ⊢ ( 𝑏  =  𝐴  →  ( 𝑎  +  𝑏 )  =  ( 𝑎  +  𝐴 ) ) | 
						
							| 110 | 109 | sbceq1d | ⊢ ( 𝑏  =  𝐴  →  ( [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓  ↔  [ ( 𝑎  +  𝐴 )  /  𝑥 ] 𝜓 ) ) | 
						
							| 111 | 110 | imbi2d | ⊢ ( 𝑏  =  𝐴  →  ( ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 )  ↔  ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝐴 )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 112 | 111 | ralbidv | ⊢ ( 𝑏  =  𝐴  →  ( ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 )  ↔  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝐴 )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 113 | 112 | elrab | ⊢ ( 𝐴  ∈  { 𝑏  ∈  𝐵  ∣  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 ) }  ↔  ( 𝐴  ∈  𝐵  ∧  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝐴 )  /  𝑥 ] 𝜓 ) ) ) | 
						
							| 114 | 113 | simprbi | ⊢ ( 𝐴  ∈  { 𝑏  ∈  𝐵  ∣  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝑏 )  /  𝑥 ] 𝜓 ) }  →  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝐴 )  /  𝑥 ] 𝜓 ) ) | 
						
							| 115 | 108 114 | syl | ⊢ ( 𝜑  →  ∀ 𝑎  ∈  𝐵 ( [ 𝑎  /  𝑥 ] 𝜓  →  [ ( 𝑎  +  𝐴 )  /  𝑥 ] 𝜓 ) ) | 
						
							| 116 | 22 115 15 | rspcdva | ⊢ ( 𝜑  →  ( [  0   /  𝑥 ] 𝜓  →  [ (  0   +  𝐴 )  /  𝑥 ] 𝜓 ) ) | 
						
							| 117 | 18 116 | mpd | ⊢ ( 𝜑  →  [ (  0   +  𝐴 )  /  𝑥 ] 𝜓 ) | 
						
							| 118 | 7 6 5 | mndlid | ⊢ ( ( 𝑀  ∈  Mnd  ∧  𝐴  ∈  𝐵 )  →  (  0   +  𝐴 )  =  𝐴 ) | 
						
							| 119 | 8 13 118 | syl2anc | ⊢ ( 𝜑  →  (  0   +  𝐴 )  =  𝐴 ) | 
						
							| 120 | 119 | sbceq1d | ⊢ ( 𝜑  →  ( [ (  0   +  𝐴 )  /  𝑥 ] 𝜓  ↔  [ 𝐴  /  𝑥 ] 𝜓 ) ) | 
						
							| 121 | 4 | sbcieg | ⊢ ( 𝐴  ∈  𝐵  →  ( [ 𝐴  /  𝑥 ] 𝜓  ↔  𝜂 ) ) | 
						
							| 122 | 13 121 | syl | ⊢ ( 𝜑  →  ( [ 𝐴  /  𝑥 ] 𝜓  ↔  𝜂 ) ) | 
						
							| 123 | 120 122 | bitrd | ⊢ ( 𝜑  →  ( [ (  0   +  𝐴 )  /  𝑥 ] 𝜓  ↔  𝜂 ) ) | 
						
							| 124 | 117 123 | mpbid | ⊢ ( 𝜑  →  𝜂 ) |