| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mgmpropd.k | ⊢ ( 𝜑  →  𝐵  =  ( Base ‘ 𝐾 ) ) | 
						
							| 2 |  | mgmpropd.l | ⊢ ( 𝜑  →  𝐵  =  ( Base ‘ 𝐿 ) ) | 
						
							| 3 |  | mgmpropd.b | ⊢ ( 𝜑  →  𝐵  ≠  ∅ ) | 
						
							| 4 |  | mgmpropd.p | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  𝐵  ∧  𝑦  ∈  𝐵 ) )  →  ( 𝑥 ( +g ‘ 𝐾 ) 𝑦 )  =  ( 𝑥 ( +g ‘ 𝐿 ) 𝑦 ) ) | 
						
							| 5 |  | simpl | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  ( Base ‘ 𝐾 )  ∧  𝑦  ∈  ( Base ‘ 𝐾 ) ) )  →  𝜑 ) | 
						
							| 6 | 1 | eqcomd | ⊢ ( 𝜑  →  ( Base ‘ 𝐾 )  =  𝐵 ) | 
						
							| 7 | 6 | eleq2d | ⊢ ( 𝜑  →  ( 𝑥  ∈  ( Base ‘ 𝐾 )  ↔  𝑥  ∈  𝐵 ) ) | 
						
							| 8 | 7 | biimpcd | ⊢ ( 𝑥  ∈  ( Base ‘ 𝐾 )  →  ( 𝜑  →  𝑥  ∈  𝐵 ) ) | 
						
							| 9 | 8 | adantr | ⊢ ( ( 𝑥  ∈  ( Base ‘ 𝐾 )  ∧  𝑦  ∈  ( Base ‘ 𝐾 ) )  →  ( 𝜑  →  𝑥  ∈  𝐵 ) ) | 
						
							| 10 | 9 | impcom | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  ( Base ‘ 𝐾 )  ∧  𝑦  ∈  ( Base ‘ 𝐾 ) ) )  →  𝑥  ∈  𝐵 ) | 
						
							| 11 | 6 | eleq2d | ⊢ ( 𝜑  →  ( 𝑦  ∈  ( Base ‘ 𝐾 )  ↔  𝑦  ∈  𝐵 ) ) | 
						
							| 12 | 11 | biimpd | ⊢ ( 𝜑  →  ( 𝑦  ∈  ( Base ‘ 𝐾 )  →  𝑦  ∈  𝐵 ) ) | 
						
							| 13 | 12 | adantld | ⊢ ( 𝜑  →  ( ( 𝑥  ∈  ( Base ‘ 𝐾 )  ∧  𝑦  ∈  ( Base ‘ 𝐾 ) )  →  𝑦  ∈  𝐵 ) ) | 
						
							| 14 | 13 | imp | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  ( Base ‘ 𝐾 )  ∧  𝑦  ∈  ( Base ‘ 𝐾 ) ) )  →  𝑦  ∈  𝐵 ) | 
						
							| 15 | 5 10 14 4 | syl12anc | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  ( Base ‘ 𝐾 )  ∧  𝑦  ∈  ( Base ‘ 𝐾 ) ) )  →  ( 𝑥 ( +g ‘ 𝐾 ) 𝑦 )  =  ( 𝑥 ( +g ‘ 𝐿 ) 𝑦 ) ) | 
						
							| 16 | 15 | eleq1d | ⊢ ( ( 𝜑  ∧  ( 𝑥  ∈  ( Base ‘ 𝐾 )  ∧  𝑦  ∈  ( Base ‘ 𝐾 ) ) )  →  ( ( 𝑥 ( +g ‘ 𝐾 ) 𝑦 )  ∈  ( Base ‘ 𝐾 )  ↔  ( 𝑥 ( +g ‘ 𝐿 ) 𝑦 )  ∈  ( Base ‘ 𝐾 ) ) ) | 
						
							| 17 | 16 | 2ralbidva | ⊢ ( 𝜑  →  ( ∀ 𝑥  ∈  ( Base ‘ 𝐾 ) ∀ 𝑦  ∈  ( Base ‘ 𝐾 ) ( 𝑥 ( +g ‘ 𝐾 ) 𝑦 )  ∈  ( Base ‘ 𝐾 )  ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐾 ) ∀ 𝑦  ∈  ( Base ‘ 𝐾 ) ( 𝑥 ( +g ‘ 𝐿 ) 𝑦 )  ∈  ( Base ‘ 𝐾 ) ) ) | 
						
							| 18 | 1 2 | eqtr3d | ⊢ ( 𝜑  →  ( Base ‘ 𝐾 )  =  ( Base ‘ 𝐿 ) ) | 
						
							| 19 | 18 | eleq2d | ⊢ ( 𝜑  →  ( ( 𝑥 ( +g ‘ 𝐿 ) 𝑦 )  ∈  ( Base ‘ 𝐾 )  ↔  ( 𝑥 ( +g ‘ 𝐿 ) 𝑦 )  ∈  ( Base ‘ 𝐿 ) ) ) | 
						
							| 20 | 18 19 | raleqbidv | ⊢ ( 𝜑  →  ( ∀ 𝑦  ∈  ( Base ‘ 𝐾 ) ( 𝑥 ( +g ‘ 𝐿 ) 𝑦 )  ∈  ( Base ‘ 𝐾 )  ↔  ∀ 𝑦  ∈  ( Base ‘ 𝐿 ) ( 𝑥 ( +g ‘ 𝐿 ) 𝑦 )  ∈  ( Base ‘ 𝐿 ) ) ) | 
						
							| 21 | 18 20 | raleqbidv | ⊢ ( 𝜑  →  ( ∀ 𝑥  ∈  ( Base ‘ 𝐾 ) ∀ 𝑦  ∈  ( Base ‘ 𝐾 ) ( 𝑥 ( +g ‘ 𝐿 ) 𝑦 )  ∈  ( Base ‘ 𝐾 )  ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐿 ) ∀ 𝑦  ∈  ( Base ‘ 𝐿 ) ( 𝑥 ( +g ‘ 𝐿 ) 𝑦 )  ∈  ( Base ‘ 𝐿 ) ) ) | 
						
							| 22 | 17 21 | bitrd | ⊢ ( 𝜑  →  ( ∀ 𝑥  ∈  ( Base ‘ 𝐾 ) ∀ 𝑦  ∈  ( Base ‘ 𝐾 ) ( 𝑥 ( +g ‘ 𝐾 ) 𝑦 )  ∈  ( Base ‘ 𝐾 )  ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐿 ) ∀ 𝑦  ∈  ( Base ‘ 𝐿 ) ( 𝑥 ( +g ‘ 𝐿 ) 𝑦 )  ∈  ( Base ‘ 𝐿 ) ) ) | 
						
							| 23 |  | n0 | ⊢ ( 𝐵  ≠  ∅  ↔  ∃ 𝑎 𝑎  ∈  𝐵 ) | 
						
							| 24 | 1 | eleq2d | ⊢ ( 𝜑  →  ( 𝑎  ∈  𝐵  ↔  𝑎  ∈  ( Base ‘ 𝐾 ) ) ) | 
						
							| 25 |  | eqid | ⊢ ( Base ‘ 𝐾 )  =  ( Base ‘ 𝐾 ) | 
						
							| 26 |  | eqid | ⊢ ( +g ‘ 𝐾 )  =  ( +g ‘ 𝐾 ) | 
						
							| 27 | 25 26 | ismgmn0 | ⊢ ( 𝑎  ∈  ( Base ‘ 𝐾 )  →  ( 𝐾  ∈  Mgm  ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐾 ) ∀ 𝑦  ∈  ( Base ‘ 𝐾 ) ( 𝑥 ( +g ‘ 𝐾 ) 𝑦 )  ∈  ( Base ‘ 𝐾 ) ) ) | 
						
							| 28 | 24 27 | biimtrdi | ⊢ ( 𝜑  →  ( 𝑎  ∈  𝐵  →  ( 𝐾  ∈  Mgm  ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐾 ) ∀ 𝑦  ∈  ( Base ‘ 𝐾 ) ( 𝑥 ( +g ‘ 𝐾 ) 𝑦 )  ∈  ( Base ‘ 𝐾 ) ) ) ) | 
						
							| 29 | 28 | exlimdv | ⊢ ( 𝜑  →  ( ∃ 𝑎 𝑎  ∈  𝐵  →  ( 𝐾  ∈  Mgm  ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐾 ) ∀ 𝑦  ∈  ( Base ‘ 𝐾 ) ( 𝑥 ( +g ‘ 𝐾 ) 𝑦 )  ∈  ( Base ‘ 𝐾 ) ) ) ) | 
						
							| 30 | 23 29 | biimtrid | ⊢ ( 𝜑  →  ( 𝐵  ≠  ∅  →  ( 𝐾  ∈  Mgm  ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐾 ) ∀ 𝑦  ∈  ( Base ‘ 𝐾 ) ( 𝑥 ( +g ‘ 𝐾 ) 𝑦 )  ∈  ( Base ‘ 𝐾 ) ) ) ) | 
						
							| 31 | 3 30 | mpd | ⊢ ( 𝜑  →  ( 𝐾  ∈  Mgm  ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐾 ) ∀ 𝑦  ∈  ( Base ‘ 𝐾 ) ( 𝑥 ( +g ‘ 𝐾 ) 𝑦 )  ∈  ( Base ‘ 𝐾 ) ) ) | 
						
							| 32 | 2 | eleq2d | ⊢ ( 𝜑  →  ( 𝑎  ∈  𝐵  ↔  𝑎  ∈  ( Base ‘ 𝐿 ) ) ) | 
						
							| 33 |  | eqid | ⊢ ( Base ‘ 𝐿 )  =  ( Base ‘ 𝐿 ) | 
						
							| 34 |  | eqid | ⊢ ( +g ‘ 𝐿 )  =  ( +g ‘ 𝐿 ) | 
						
							| 35 | 33 34 | ismgmn0 | ⊢ ( 𝑎  ∈  ( Base ‘ 𝐿 )  →  ( 𝐿  ∈  Mgm  ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐿 ) ∀ 𝑦  ∈  ( Base ‘ 𝐿 ) ( 𝑥 ( +g ‘ 𝐿 ) 𝑦 )  ∈  ( Base ‘ 𝐿 ) ) ) | 
						
							| 36 | 32 35 | biimtrdi | ⊢ ( 𝜑  →  ( 𝑎  ∈  𝐵  →  ( 𝐿  ∈  Mgm  ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐿 ) ∀ 𝑦  ∈  ( Base ‘ 𝐿 ) ( 𝑥 ( +g ‘ 𝐿 ) 𝑦 )  ∈  ( Base ‘ 𝐿 ) ) ) ) | 
						
							| 37 | 36 | exlimdv | ⊢ ( 𝜑  →  ( ∃ 𝑎 𝑎  ∈  𝐵  →  ( 𝐿  ∈  Mgm  ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐿 ) ∀ 𝑦  ∈  ( Base ‘ 𝐿 ) ( 𝑥 ( +g ‘ 𝐿 ) 𝑦 )  ∈  ( Base ‘ 𝐿 ) ) ) ) | 
						
							| 38 | 23 37 | biimtrid | ⊢ ( 𝜑  →  ( 𝐵  ≠  ∅  →  ( 𝐿  ∈  Mgm  ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐿 ) ∀ 𝑦  ∈  ( Base ‘ 𝐿 ) ( 𝑥 ( +g ‘ 𝐿 ) 𝑦 )  ∈  ( Base ‘ 𝐿 ) ) ) ) | 
						
							| 39 | 3 38 | mpd | ⊢ ( 𝜑  →  ( 𝐿  ∈  Mgm  ↔  ∀ 𝑥  ∈  ( Base ‘ 𝐿 ) ∀ 𝑦  ∈  ( Base ‘ 𝐿 ) ( 𝑥 ( +g ‘ 𝐿 ) 𝑦 )  ∈  ( Base ‘ 𝐿 ) ) ) | 
						
							| 40 | 22 31 39 | 3bitr4d | ⊢ ( 𝜑  →  ( 𝐾  ∈  Mgm  ↔  𝐿  ∈  Mgm ) ) |