| Step | Hyp | Ref | Expression | 
						
							| 1 |  | phlsrng.f | ⊢ 𝐹  =  ( Scalar ‘ 𝑊 ) | 
						
							| 2 |  | phllmhm.h | ⊢  ,   =  ( ·𝑖 ‘ 𝑊 ) | 
						
							| 3 |  | phllmhm.v | ⊢ 𝑉  =  ( Base ‘ 𝑊 ) | 
						
							| 4 |  | ipsubdir.m | ⊢  −   =  ( -g ‘ 𝑊 ) | 
						
							| 5 |  | ipsubdir.s | ⊢ 𝑆  =  ( -g ‘ 𝐹 ) | 
						
							| 6 |  | ip2subdi.p | ⊢  +   =  ( +g ‘ 𝐹 ) | 
						
							| 7 |  | ip2subdi.1 | ⊢ ( 𝜑  →  𝑊  ∈  PreHil ) | 
						
							| 8 |  | ip2subdi.2 | ⊢ ( 𝜑  →  𝐴  ∈  𝑉 ) | 
						
							| 9 |  | ip2subdi.3 | ⊢ ( 𝜑  →  𝐵  ∈  𝑉 ) | 
						
							| 10 |  | ip2subdi.4 | ⊢ ( 𝜑  →  𝐶  ∈  𝑉 ) | 
						
							| 11 |  | ip2subdi.5 | ⊢ ( 𝜑  →  𝐷  ∈  𝑉 ) | 
						
							| 12 |  | eqid | ⊢ ( Base ‘ 𝐹 )  =  ( Base ‘ 𝐹 ) | 
						
							| 13 |  | phllmod | ⊢ ( 𝑊  ∈  PreHil  →  𝑊  ∈  LMod ) | 
						
							| 14 | 7 13 | syl | ⊢ ( 𝜑  →  𝑊  ∈  LMod ) | 
						
							| 15 | 1 | lmodring | ⊢ ( 𝑊  ∈  LMod  →  𝐹  ∈  Ring ) | 
						
							| 16 | 14 15 | syl | ⊢ ( 𝜑  →  𝐹  ∈  Ring ) | 
						
							| 17 |  | ringabl | ⊢ ( 𝐹  ∈  Ring  →  𝐹  ∈  Abel ) | 
						
							| 18 | 16 17 | syl | ⊢ ( 𝜑  →  𝐹  ∈  Abel ) | 
						
							| 19 | 1 2 3 12 | ipcl | ⊢ ( ( 𝑊  ∈  PreHil  ∧  𝐴  ∈  𝑉  ∧  𝐶  ∈  𝑉 )  →  ( 𝐴  ,  𝐶 )  ∈  ( Base ‘ 𝐹 ) ) | 
						
							| 20 | 7 8 10 19 | syl3anc | ⊢ ( 𝜑  →  ( 𝐴  ,  𝐶 )  ∈  ( Base ‘ 𝐹 ) ) | 
						
							| 21 | 1 2 3 12 | ipcl | ⊢ ( ( 𝑊  ∈  PreHil  ∧  𝐴  ∈  𝑉  ∧  𝐷  ∈  𝑉 )  →  ( 𝐴  ,  𝐷 )  ∈  ( Base ‘ 𝐹 ) ) | 
						
							| 22 | 7 8 11 21 | syl3anc | ⊢ ( 𝜑  →  ( 𝐴  ,  𝐷 )  ∈  ( Base ‘ 𝐹 ) ) | 
						
							| 23 | 1 2 3 12 | ipcl | ⊢ ( ( 𝑊  ∈  PreHil  ∧  𝐵  ∈  𝑉  ∧  𝐶  ∈  𝑉 )  →  ( 𝐵  ,  𝐶 )  ∈  ( Base ‘ 𝐹 ) ) | 
						
							| 24 | 7 9 10 23 | syl3anc | ⊢ ( 𝜑  →  ( 𝐵  ,  𝐶 )  ∈  ( Base ‘ 𝐹 ) ) | 
						
							| 25 | 12 6 5 18 20 22 24 | ablsubsub4 | ⊢ ( 𝜑  →  ( ( ( 𝐴  ,  𝐶 ) 𝑆 ( 𝐴  ,  𝐷 ) ) 𝑆 ( 𝐵  ,  𝐶 ) )  =  ( ( 𝐴  ,  𝐶 ) 𝑆 ( ( 𝐴  ,  𝐷 )  +  ( 𝐵  ,  𝐶 ) ) ) ) | 
						
							| 26 | 25 | oveq1d | ⊢ ( 𝜑  →  ( ( ( ( 𝐴  ,  𝐶 ) 𝑆 ( 𝐴  ,  𝐷 ) ) 𝑆 ( 𝐵  ,  𝐶 ) )  +  ( 𝐵  ,  𝐷 ) )  =  ( ( ( 𝐴  ,  𝐶 ) 𝑆 ( ( 𝐴  ,  𝐷 )  +  ( 𝐵  ,  𝐶 ) ) )  +  ( 𝐵  ,  𝐷 ) ) ) | 
						
							| 27 | 3 4 | lmodvsubcl | ⊢ ( ( 𝑊  ∈  LMod  ∧  𝐶  ∈  𝑉  ∧  𝐷  ∈  𝑉 )  →  ( 𝐶  −  𝐷 )  ∈  𝑉 ) | 
						
							| 28 | 14 10 11 27 | syl3anc | ⊢ ( 𝜑  →  ( 𝐶  −  𝐷 )  ∈  𝑉 ) | 
						
							| 29 | 1 2 3 4 5 | ipsubdir | ⊢ ( ( 𝑊  ∈  PreHil  ∧  ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑉  ∧  ( 𝐶  −  𝐷 )  ∈  𝑉 ) )  →  ( ( 𝐴  −  𝐵 )  ,  ( 𝐶  −  𝐷 ) )  =  ( ( 𝐴  ,  ( 𝐶  −  𝐷 ) ) 𝑆 ( 𝐵  ,  ( 𝐶  −  𝐷 ) ) ) ) | 
						
							| 30 | 7 8 9 28 29 | syl13anc | ⊢ ( 𝜑  →  ( ( 𝐴  −  𝐵 )  ,  ( 𝐶  −  𝐷 ) )  =  ( ( 𝐴  ,  ( 𝐶  −  𝐷 ) ) 𝑆 ( 𝐵  ,  ( 𝐶  −  𝐷 ) ) ) ) | 
						
							| 31 | 1 2 3 4 5 | ipsubdi | ⊢ ( ( 𝑊  ∈  PreHil  ∧  ( 𝐴  ∈  𝑉  ∧  𝐶  ∈  𝑉  ∧  𝐷  ∈  𝑉 ) )  →  ( 𝐴  ,  ( 𝐶  −  𝐷 ) )  =  ( ( 𝐴  ,  𝐶 ) 𝑆 ( 𝐴  ,  𝐷 ) ) ) | 
						
							| 32 | 7 8 10 11 31 | syl13anc | ⊢ ( 𝜑  →  ( 𝐴  ,  ( 𝐶  −  𝐷 ) )  =  ( ( 𝐴  ,  𝐶 ) 𝑆 ( 𝐴  ,  𝐷 ) ) ) | 
						
							| 33 | 1 2 3 4 5 | ipsubdi | ⊢ ( ( 𝑊  ∈  PreHil  ∧  ( 𝐵  ∈  𝑉  ∧  𝐶  ∈  𝑉  ∧  𝐷  ∈  𝑉 ) )  →  ( 𝐵  ,  ( 𝐶  −  𝐷 ) )  =  ( ( 𝐵  ,  𝐶 ) 𝑆 ( 𝐵  ,  𝐷 ) ) ) | 
						
							| 34 | 7 9 10 11 33 | syl13anc | ⊢ ( 𝜑  →  ( 𝐵  ,  ( 𝐶  −  𝐷 ) )  =  ( ( 𝐵  ,  𝐶 ) 𝑆 ( 𝐵  ,  𝐷 ) ) ) | 
						
							| 35 | 32 34 | oveq12d | ⊢ ( 𝜑  →  ( ( 𝐴  ,  ( 𝐶  −  𝐷 ) ) 𝑆 ( 𝐵  ,  ( 𝐶  −  𝐷 ) ) )  =  ( ( ( 𝐴  ,  𝐶 ) 𝑆 ( 𝐴  ,  𝐷 ) ) 𝑆 ( ( 𝐵  ,  𝐶 ) 𝑆 ( 𝐵  ,  𝐷 ) ) ) ) | 
						
							| 36 |  | ringgrp | ⊢ ( 𝐹  ∈  Ring  →  𝐹  ∈  Grp ) | 
						
							| 37 | 16 36 | syl | ⊢ ( 𝜑  →  𝐹  ∈  Grp ) | 
						
							| 38 | 12 5 | grpsubcl | ⊢ ( ( 𝐹  ∈  Grp  ∧  ( 𝐴  ,  𝐶 )  ∈  ( Base ‘ 𝐹 )  ∧  ( 𝐴  ,  𝐷 )  ∈  ( Base ‘ 𝐹 ) )  →  ( ( 𝐴  ,  𝐶 ) 𝑆 ( 𝐴  ,  𝐷 ) )  ∈  ( Base ‘ 𝐹 ) ) | 
						
							| 39 | 37 20 22 38 | syl3anc | ⊢ ( 𝜑  →  ( ( 𝐴  ,  𝐶 ) 𝑆 ( 𝐴  ,  𝐷 ) )  ∈  ( Base ‘ 𝐹 ) ) | 
						
							| 40 | 1 2 3 12 | ipcl | ⊢ ( ( 𝑊  ∈  PreHil  ∧  𝐵  ∈  𝑉  ∧  𝐷  ∈  𝑉 )  →  ( 𝐵  ,  𝐷 )  ∈  ( Base ‘ 𝐹 ) ) | 
						
							| 41 | 7 9 11 40 | syl3anc | ⊢ ( 𝜑  →  ( 𝐵  ,  𝐷 )  ∈  ( Base ‘ 𝐹 ) ) | 
						
							| 42 | 12 6 5 18 39 24 41 | ablsubsub | ⊢ ( 𝜑  →  ( ( ( 𝐴  ,  𝐶 ) 𝑆 ( 𝐴  ,  𝐷 ) ) 𝑆 ( ( 𝐵  ,  𝐶 ) 𝑆 ( 𝐵  ,  𝐷 ) ) )  =  ( ( ( ( 𝐴  ,  𝐶 ) 𝑆 ( 𝐴  ,  𝐷 ) ) 𝑆 ( 𝐵  ,  𝐶 ) )  +  ( 𝐵  ,  𝐷 ) ) ) | 
						
							| 43 | 30 35 42 | 3eqtrd | ⊢ ( 𝜑  →  ( ( 𝐴  −  𝐵 )  ,  ( 𝐶  −  𝐷 ) )  =  ( ( ( ( 𝐴  ,  𝐶 ) 𝑆 ( 𝐴  ,  𝐷 ) ) 𝑆 ( 𝐵  ,  𝐶 ) )  +  ( 𝐵  ,  𝐷 ) ) ) | 
						
							| 44 | 12 6 | ringacl | ⊢ ( ( 𝐹  ∈  Ring  ∧  ( 𝐴  ,  𝐷 )  ∈  ( Base ‘ 𝐹 )  ∧  ( 𝐵  ,  𝐶 )  ∈  ( Base ‘ 𝐹 ) )  →  ( ( 𝐴  ,  𝐷 )  +  ( 𝐵  ,  𝐶 ) )  ∈  ( Base ‘ 𝐹 ) ) | 
						
							| 45 | 16 22 24 44 | syl3anc | ⊢ ( 𝜑  →  ( ( 𝐴  ,  𝐷 )  +  ( 𝐵  ,  𝐶 ) )  ∈  ( Base ‘ 𝐹 ) ) | 
						
							| 46 | 12 6 5 | abladdsub | ⊢ ( ( 𝐹  ∈  Abel  ∧  ( ( 𝐴  ,  𝐶 )  ∈  ( Base ‘ 𝐹 )  ∧  ( 𝐵  ,  𝐷 )  ∈  ( Base ‘ 𝐹 )  ∧  ( ( 𝐴  ,  𝐷 )  +  ( 𝐵  ,  𝐶 ) )  ∈  ( Base ‘ 𝐹 ) ) )  →  ( ( ( 𝐴  ,  𝐶 )  +  ( 𝐵  ,  𝐷 ) ) 𝑆 ( ( 𝐴  ,  𝐷 )  +  ( 𝐵  ,  𝐶 ) ) )  =  ( ( ( 𝐴  ,  𝐶 ) 𝑆 ( ( 𝐴  ,  𝐷 )  +  ( 𝐵  ,  𝐶 ) ) )  +  ( 𝐵  ,  𝐷 ) ) ) | 
						
							| 47 | 18 20 41 45 46 | syl13anc | ⊢ ( 𝜑  →  ( ( ( 𝐴  ,  𝐶 )  +  ( 𝐵  ,  𝐷 ) ) 𝑆 ( ( 𝐴  ,  𝐷 )  +  ( 𝐵  ,  𝐶 ) ) )  =  ( ( ( 𝐴  ,  𝐶 ) 𝑆 ( ( 𝐴  ,  𝐷 )  +  ( 𝐵  ,  𝐶 ) ) )  +  ( 𝐵  ,  𝐷 ) ) ) | 
						
							| 48 | 26 43 47 | 3eqtr4d | ⊢ ( 𝜑  →  ( ( 𝐴  −  𝐵 )  ,  ( 𝐶  −  𝐷 ) )  =  ( ( ( 𝐴  ,  𝐶 )  +  ( 𝐵  ,  𝐷 ) ) 𝑆 ( ( 𝐴  ,  𝐷 )  +  ( 𝐵  ,  𝐶 ) ) ) ) |