| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ditgsplit.x | ⊢ ( 𝜑  →  𝑋  ∈  ℝ ) | 
						
							| 2 |  | ditgsplit.y | ⊢ ( 𝜑  →  𝑌  ∈  ℝ ) | 
						
							| 3 |  | ditgsplit.a | ⊢ ( 𝜑  →  𝐴  ∈  ( 𝑋 [,] 𝑌 ) ) | 
						
							| 4 |  | ditgsplit.b | ⊢ ( 𝜑  →  𝐵  ∈  ( 𝑋 [,] 𝑌 ) ) | 
						
							| 5 |  | ditgsplit.c | ⊢ ( 𝜑  →  𝐶  ∈  ( 𝑋 [,] 𝑌 ) ) | 
						
							| 6 |  | ditgsplit.d | ⊢ ( ( 𝜑  ∧  𝑥  ∈  ( 𝑋 (,) 𝑌 ) )  →  𝐷  ∈  𝑉 ) | 
						
							| 7 |  | ditgsplit.i | ⊢ ( 𝜑  →  ( 𝑥  ∈  ( 𝑋 (,) 𝑌 )  ↦  𝐷 )  ∈  𝐿1 ) | 
						
							| 8 |  | elicc2 | ⊢ ( ( 𝑋  ∈  ℝ  ∧  𝑌  ∈  ℝ )  →  ( 𝐴  ∈  ( 𝑋 [,] 𝑌 )  ↔  ( 𝐴  ∈  ℝ  ∧  𝑋  ≤  𝐴  ∧  𝐴  ≤  𝑌 ) ) ) | 
						
							| 9 | 1 2 8 | syl2anc | ⊢ ( 𝜑  →  ( 𝐴  ∈  ( 𝑋 [,] 𝑌 )  ↔  ( 𝐴  ∈  ℝ  ∧  𝑋  ≤  𝐴  ∧  𝐴  ≤  𝑌 ) ) ) | 
						
							| 10 | 3 9 | mpbid | ⊢ ( 𝜑  →  ( 𝐴  ∈  ℝ  ∧  𝑋  ≤  𝐴  ∧  𝐴  ≤  𝑌 ) ) | 
						
							| 11 | 10 | simp1d | ⊢ ( 𝜑  →  𝐴  ∈  ℝ ) | 
						
							| 12 |  | elicc2 | ⊢ ( ( 𝑋  ∈  ℝ  ∧  𝑌  ∈  ℝ )  →  ( 𝐵  ∈  ( 𝑋 [,] 𝑌 )  ↔  ( 𝐵  ∈  ℝ  ∧  𝑋  ≤  𝐵  ∧  𝐵  ≤  𝑌 ) ) ) | 
						
							| 13 | 1 2 12 | syl2anc | ⊢ ( 𝜑  →  ( 𝐵  ∈  ( 𝑋 [,] 𝑌 )  ↔  ( 𝐵  ∈  ℝ  ∧  𝑋  ≤  𝐵  ∧  𝐵  ≤  𝑌 ) ) ) | 
						
							| 14 | 4 13 | mpbid | ⊢ ( 𝜑  →  ( 𝐵  ∈  ℝ  ∧  𝑋  ≤  𝐵  ∧  𝐵  ≤  𝑌 ) ) | 
						
							| 15 | 14 | simp1d | ⊢ ( 𝜑  →  𝐵  ∈  ℝ ) | 
						
							| 16 | 11 | adantr | ⊢ ( ( 𝜑  ∧  𝐴  ≤  𝐵 )  →  𝐴  ∈  ℝ ) | 
						
							| 17 |  | elicc2 | ⊢ ( ( 𝑋  ∈  ℝ  ∧  𝑌  ∈  ℝ )  →  ( 𝐶  ∈  ( 𝑋 [,] 𝑌 )  ↔  ( 𝐶  ∈  ℝ  ∧  𝑋  ≤  𝐶  ∧  𝐶  ≤  𝑌 ) ) ) | 
						
							| 18 | 1 2 17 | syl2anc | ⊢ ( 𝜑  →  ( 𝐶  ∈  ( 𝑋 [,] 𝑌 )  ↔  ( 𝐶  ∈  ℝ  ∧  𝑋  ≤  𝐶  ∧  𝐶  ≤  𝑌 ) ) ) | 
						
							| 19 | 5 18 | mpbid | ⊢ ( 𝜑  →  ( 𝐶  ∈  ℝ  ∧  𝑋  ≤  𝐶  ∧  𝐶  ≤  𝑌 ) ) | 
						
							| 20 | 19 | simp1d | ⊢ ( 𝜑  →  𝐶  ∈  ℝ ) | 
						
							| 21 | 20 | adantr | ⊢ ( ( 𝜑  ∧  𝐴  ≤  𝐵 )  →  𝐶  ∈  ℝ ) | 
						
							| 22 | 15 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝐴  ≤  𝐵 )  ∧  𝐴  ≤  𝐶 )  →  𝐵  ∈  ℝ ) | 
						
							| 23 | 20 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝐴  ≤  𝐵 )  ∧  𝐴  ≤  𝐶 )  →  𝐶  ∈  ℝ ) | 
						
							| 24 |  | biid | ⊢ ( ( 𝐴  ≤  𝐵  ∧  𝐵  ≤  𝐶 )  ↔  ( 𝐴  ≤  𝐵  ∧  𝐵  ≤  𝐶 ) ) | 
						
							| 25 | 1 2 3 4 5 6 7 24 | ditgsplitlem | ⊢ ( ( ( 𝜑  ∧  𝐴  ≤  𝐵 )  ∧  𝐵  ≤  𝐶 )  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 26 | 25 | adantlr | ⊢ ( ( ( ( 𝜑  ∧  𝐴  ≤  𝐵 )  ∧  𝐴  ≤  𝐶 )  ∧  𝐵  ≤  𝐶 )  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 27 |  | biid | ⊢ ( ( 𝐴  ≤  𝐶  ∧  𝐶  ≤  𝐵 )  ↔  ( 𝐴  ≤  𝐶  ∧  𝐶  ≤  𝐵 ) ) | 
						
							| 28 | 1 2 3 5 4 6 7 27 | ditgsplitlem | ⊢ ( ( ( 𝜑  ∧  𝐴  ≤  𝐶 )  ∧  𝐶  ≤  𝐵 )  →  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 ) ) | 
						
							| 29 | 28 | oveq1d | ⊢ ( ( ( 𝜑  ∧  𝐴  ≤  𝐶 )  ∧  𝐶  ≤  𝐵 )  →  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 )  =  ( ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 30 | 1 2 3 5 6 7 | ditgcl | ⊢ ( 𝜑  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  ∈  ℂ ) | 
						
							| 31 | 1 2 5 4 6 7 | ditgcl | ⊢ ( 𝜑  →  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  ∈  ℂ ) | 
						
							| 32 | 1 2 4 5 6 7 | ditgcl | ⊢ ( 𝜑  →  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥  ∈  ℂ ) | 
						
							| 33 | 30 31 32 | addassd | ⊢ ( 𝜑  →  ( ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 )  =  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) ) | 
						
							| 34 | 1 2 5 4 6 7 | ditgswap | ⊢ ( 𝜑  →  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥  =  - ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 ) | 
						
							| 35 | 34 | oveq2d | ⊢ ( 𝜑  →  ( ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 )  =  ( ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  +  - ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 ) ) | 
						
							| 36 | 31 | negidd | ⊢ ( 𝜑  →  ( ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  +  - ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 )  =  0 ) | 
						
							| 37 | 35 36 | eqtrd | ⊢ ( 𝜑  →  ( ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 )  =  0 ) | 
						
							| 38 | 37 | oveq2d | ⊢ ( 𝜑  →  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) )  =  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  0 ) ) | 
						
							| 39 | 30 | addridd | ⊢ ( 𝜑  →  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  0 )  =  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) | 
						
							| 40 | 33 38 39 | 3eqtrd | ⊢ ( 𝜑  →  ( ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 )  =  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) | 
						
							| 41 | 40 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝐴  ≤  𝐶 )  ∧  𝐶  ≤  𝐵 )  →  ( ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 )  =  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) | 
						
							| 42 | 29 41 | eqtr2d | ⊢ ( ( ( 𝜑  ∧  𝐴  ≤  𝐶 )  ∧  𝐶  ≤  𝐵 )  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 43 | 42 | adantllr | ⊢ ( ( ( ( 𝜑  ∧  𝐴  ≤  𝐵 )  ∧  𝐴  ≤  𝐶 )  ∧  𝐶  ≤  𝐵 )  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 44 | 22 23 26 43 | lecasei | ⊢ ( ( ( 𝜑  ∧  𝐴  ≤  𝐵 )  ∧  𝐴  ≤  𝐶 )  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 45 | 40 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝐴  ≤  𝐵 )  ∧  𝐶  ≤  𝐴 )  →  ( ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 )  =  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) | 
						
							| 46 |  | ancom | ⊢ ( ( 𝐴  ≤  𝐵  ∧  𝐶  ≤  𝐴 )  ↔  ( 𝐶  ≤  𝐴  ∧  𝐴  ≤  𝐵 ) ) | 
						
							| 47 | 1 2 5 3 4 6 7 46 | ditgsplitlem | ⊢ ( ( ( 𝜑  ∧  𝐴  ≤  𝐵 )  ∧  𝐶  ≤  𝐴 )  →  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) ) | 
						
							| 48 | 47 | oveq2d | ⊢ ( ( ( 𝜑  ∧  𝐴  ≤  𝐵 )  ∧  𝐶  ≤  𝐴 )  →  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 )  =  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) ) ) | 
						
							| 49 | 1 2 3 5 6 7 | ditgswap | ⊢ ( 𝜑  →  ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  =  - ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) | 
						
							| 50 | 49 | oveq2d | ⊢ ( 𝜑  →  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥 )  =  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  - ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 51 | 30 | negidd | ⊢ ( 𝜑  →  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  - ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 )  =  0 ) | 
						
							| 52 | 50 51 | eqtrd | ⊢ ( 𝜑  →  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥 )  =  0 ) | 
						
							| 53 | 52 | oveq1d | ⊢ ( 𝜑  →  ( ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 )  =  ( 0  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) ) | 
						
							| 54 | 1 2 5 3 6 7 | ditgcl | ⊢ ( 𝜑  →  ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  ∈  ℂ ) | 
						
							| 55 | 1 2 3 4 6 7 | ditgcl | ⊢ ( 𝜑  →  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  ∈  ℂ ) | 
						
							| 56 | 30 54 55 | addassd | ⊢ ( 𝜑  →  ( ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 )  =  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) ) ) | 
						
							| 57 | 55 | addlidd | ⊢ ( 𝜑  →  ( 0  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 )  =  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) | 
						
							| 58 | 53 56 57 | 3eqtr3d | ⊢ ( 𝜑  →  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) )  =  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) | 
						
							| 59 | 58 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝐴  ≤  𝐵 )  ∧  𝐶  ≤  𝐴 )  →  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) )  =  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) | 
						
							| 60 | 48 59 | eqtrd | ⊢ ( ( ( 𝜑  ∧  𝐴  ≤  𝐵 )  ∧  𝐶  ≤  𝐴 )  →  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 )  =  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) | 
						
							| 61 | 60 | oveq1d | ⊢ ( ( ( 𝜑  ∧  𝐴  ≤  𝐵 )  ∧  𝐶  ≤  𝐴 )  →  ( ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 )  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 62 | 45 61 | eqtr3d | ⊢ ( ( ( 𝜑  ∧  𝐴  ≤  𝐵 )  ∧  𝐶  ≤  𝐴 )  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 63 | 16 21 44 62 | lecasei | ⊢ ( ( 𝜑  ∧  𝐴  ≤  𝐵 )  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 64 | 11 | adantr | ⊢ ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  →  𝐴  ∈  ℝ ) | 
						
							| 65 | 20 | adantr | ⊢ ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  →  𝐶  ∈  ℝ ) | 
						
							| 66 |  | biid | ⊢ ( ( 𝐵  ≤  𝐴  ∧  𝐴  ≤  𝐶 )  ↔  ( 𝐵  ≤  𝐴  ∧  𝐴  ≤  𝐶 ) ) | 
						
							| 67 | 1 2 4 3 5 6 7 66 | ditgsplitlem | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐴  ≤  𝐶 )  →  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 68 | 67 | oveq2d | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐴  ≤  𝐶 )  →  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 )  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) ) ) | 
						
							| 69 | 1 2 3 4 6 7 | ditgswap | ⊢ ( 𝜑  →  ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  =  - ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) | 
						
							| 70 | 69 | oveq2d | ⊢ ( 𝜑  →  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥 )  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  - ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) ) | 
						
							| 71 | 55 | negidd | ⊢ ( 𝜑  →  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  - ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 )  =  0 ) | 
						
							| 72 | 70 71 | eqtrd | ⊢ ( 𝜑  →  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥 )  =  0 ) | 
						
							| 73 | 72 | oveq1d | ⊢ ( 𝜑  →  ( ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 )  =  ( 0  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 74 | 1 2 4 3 6 7 | ditgcl | ⊢ ( 𝜑  →  ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  ∈  ℂ ) | 
						
							| 75 | 55 74 30 | addassd | ⊢ ( 𝜑  →  ( ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 )  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) ) ) | 
						
							| 76 | 30 | addlidd | ⊢ ( 𝜑  →  ( 0  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 )  =  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) | 
						
							| 77 | 73 75 76 | 3eqtr3d | ⊢ ( 𝜑  →  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) )  =  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) | 
						
							| 78 | 77 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐴  ≤  𝐶 )  →  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) )  =  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) | 
						
							| 79 | 68 78 | eqtr2d | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐴  ≤  𝐶 )  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 80 | 15 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐶  ≤  𝐴 )  →  𝐵  ∈  ℝ ) | 
						
							| 81 | 20 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐶  ≤  𝐴 )  →  𝐶  ∈  ℝ ) | 
						
							| 82 |  | ancom | ⊢ ( ( 𝐶  ≤  𝐴  ∧  𝐵  ≤  𝐶 )  ↔  ( 𝐵  ≤  𝐶  ∧  𝐶  ≤  𝐴 ) ) | 
						
							| 83 | 1 2 4 5 3 6 7 82 | ditgsplitlem | ⊢ ( ( ( 𝜑  ∧  𝐶  ≤  𝐴 )  ∧  𝐵  ≤  𝐶 )  →  ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥 ) ) | 
						
							| 84 | 83 | oveq1d | ⊢ ( ( ( 𝜑  ∧  𝐶  ≤  𝐴 )  ∧  𝐵  ≤  𝐶 )  →  ( ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 )  =  ( ( ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 85 | 32 54 30 | addassd | ⊢ ( 𝜑  →  ( ( ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 )  =  ( ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) ) ) | 
						
							| 86 | 1 2 5 3 6 7 | ditgswap | ⊢ ( 𝜑  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  =  - ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥 ) | 
						
							| 87 | 86 | oveq2d | ⊢ ( 𝜑  →  ( ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 )  =  ( ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  +  - ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥 ) ) | 
						
							| 88 | 54 | negidd | ⊢ ( 𝜑  →  ( ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  +  - ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥 )  =  0 ) | 
						
							| 89 | 87 88 | eqtrd | ⊢ ( 𝜑  →  ( ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 )  =  0 ) | 
						
							| 90 | 89 | oveq2d | ⊢ ( 𝜑  →  ( ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) )  =  ( ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥  +  0 ) ) | 
						
							| 91 | 32 | addridd | ⊢ ( 𝜑  →  ( ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥  +  0 )  =  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) | 
						
							| 92 | 85 90 91 | 3eqtrd | ⊢ ( 𝜑  →  ( ( ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 )  =  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) | 
						
							| 93 | 92 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝐶  ≤  𝐴 )  ∧  𝐵  ≤  𝐶 )  →  ( ( ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 )  =  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) | 
						
							| 94 | 84 93 | eqtr2d | ⊢ ( ( ( 𝜑  ∧  𝐶  ≤  𝐴 )  ∧  𝐵  ≤  𝐶 )  →  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 95 | 94 | oveq2d | ⊢ ( ( ( 𝜑  ∧  𝐶  ≤  𝐴 )  ∧  𝐵  ≤  𝐶 )  →  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 )  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) ) ) | 
						
							| 96 | 77 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝐶  ≤  𝐴 )  ∧  𝐵  ≤  𝐶 )  →  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) )  =  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) | 
						
							| 97 | 95 96 | eqtr2d | ⊢ ( ( ( 𝜑  ∧  𝐶  ≤  𝐴 )  ∧  𝐵  ≤  𝐶 )  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 98 | 97 | adantllr | ⊢ ( ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐶  ≤  𝐴 )  ∧  𝐵  ≤  𝐶 )  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 99 |  | ancom | ⊢ ( ( 𝐵  ≤  𝐴  ∧  𝐶  ≤  𝐵 )  ↔  ( 𝐶  ≤  𝐵  ∧  𝐵  ≤  𝐴 ) ) | 
						
							| 100 | 1 2 5 4 3 6 7 99 | ditgsplitlem | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐶  ≤  𝐵 )  →  ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥 ) ) | 
						
							| 101 | 100 | oveq1d | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐶  ≤  𝐵 )  →  ( ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 )  =  ( ( ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) ) | 
						
							| 102 | 31 74 55 | addassd | ⊢ ( 𝜑  →  ( ( ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 )  =  ( ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) ) ) | 
						
							| 103 | 1 2 4 3 6 7 | ditgswap | ⊢ ( 𝜑  →  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  =  - ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥 ) | 
						
							| 104 | 103 | oveq2d | ⊢ ( 𝜑  →  ( ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 )  =  ( ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  +  - ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥 ) ) | 
						
							| 105 | 74 | negidd | ⊢ ( 𝜑  →  ( ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  +  - ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥 )  =  0 ) | 
						
							| 106 | 104 105 | eqtrd | ⊢ ( 𝜑  →  ( ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 )  =  0 ) | 
						
							| 107 | 106 | oveq2d | ⊢ ( 𝜑  →  ( ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) )  =  ( ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  +  0 ) ) | 
						
							| 108 | 31 | addridd | ⊢ ( 𝜑  →  ( ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  +  0 )  =  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 ) | 
						
							| 109 | 102 107 108 | 3eqtrd | ⊢ ( 𝜑  →  ( ( ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 )  =  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 ) | 
						
							| 110 | 109 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐶  ≤  𝐵 )  →  ( ( ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐴 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 )  =  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 ) | 
						
							| 111 | 101 110 | eqtr2d | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐶  ≤  𝐵 )  →  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) ) | 
						
							| 112 | 111 | oveq2d | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐶  ≤  𝐵 )  →  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 )  =  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) ) ) | 
						
							| 113 | 58 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐶  ≤  𝐵 )  →  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ( ⨜ [ 𝐶  →  𝐴 ] 𝐷  d 𝑥  +  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) )  =  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥 ) | 
						
							| 114 | 112 113 | eqtr2d | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐶  ≤  𝐵 )  →  ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 ) ) | 
						
							| 115 | 114 | oveq1d | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐶  ≤  𝐵 )  →  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 )  =  ( ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 116 | 40 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐶  ≤  𝐵 )  →  ( ( ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  +  ⨜ [ 𝐶  →  𝐵 ] 𝐷  d 𝑥 )  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 )  =  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥 ) | 
						
							| 117 | 115 116 | eqtr2d | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐶  ≤  𝐵 )  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 118 | 117 | adantlr | ⊢ ( ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐶  ≤  𝐴 )  ∧  𝐶  ≤  𝐵 )  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 119 | 80 81 98 118 | lecasei | ⊢ ( ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  ∧  𝐶  ≤  𝐴 )  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 120 | 64 65 79 119 | lecasei | ⊢ ( ( 𝜑  ∧  𝐵  ≤  𝐴 )  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) | 
						
							| 121 | 11 15 63 120 | lecasei | ⊢ ( 𝜑  →  ⨜ [ 𝐴  →  𝐶 ] 𝐷  d 𝑥  =  ( ⨜ [ 𝐴  →  𝐵 ] 𝐷  d 𝑥  +  ⨜ [ 𝐵  →  𝐶 ] 𝐷  d 𝑥 ) ) |