[{"type":"thinking","thinking":"Down to ONE error: line 403:8 \"No goals to be solved\". Line 403 is in the final assembly — the step-5 `congr 1` — congr closed BOTH subgoals (A = A' via... hmm no — A = A' is `∫-T..-10 = ∫10..T` which is hleft — not rfl!). Wait — \"No goals to be solved\" at 403:8 — let me figure out which line is 403 now. The congr 1 + exact hleft step: if congr 1 closed all goals (maybe congr closed the goal ENTIRELY via defeq?? — the two sides ARE equal up to hleft — not defeq!). Hmm — actually wait: maybe congr 1's auto-rfl closed everything because... no. Let me count: line 403 in the current file. The step-5 block:\n\n```\n    _ = (∫ t in (10 : ℝ)..T, ...) +\n          ((∫ t in (-10 : ℝ)..(10 : ℝ), ...) +\n            (∫ t in (10 : ℝ)..T, ...)) := by\n        congr 1\n        exact hleft\n```\n\n`congr 1` — then `exact hleft` — if congr 1 closed ALL goals (e.g., it solved A = A' by... no, it can't without hleft)... OR congr 1 produced ONE goal (A = A') and closed the rfl one, and... `exact hleft` says \"No goals\" — meaning congr 1 closed EVERYTHING. How? congr's auto-rfl uses defeq — A = A' is `∫-T..-10, F = ∫10..T, F` — NOT defeq... \n\nUNLESS — congr 1 turned the goal into something trivially closed: maybe congr failed to split and instead closed via... hmm. OR: congr 1 on `HAdd X Y = HAdd X' Y'` — with X = ∫-T..-10 and X' = ∫10..T — it might have used `hleft`?? No — congr doesn't know hleft.\n\nWait — \"No goals to be solved\" at 403:8 — col 8 — which tactic is at col 8? The `congr 1` line is at col 8 (8 spaces indent). So congr 1 ITSELF reports \"No goals to be solved\"?! That happens when congr 1 runs with... no goals? Or the error is at `exact hleft` (also col 8, next line). Line numbers: let me count from my edit. The calc starts around line 380. Step 5's `:= by` then `congr 1` then `exact hleft`. If `congr 1` is line 403 and `exact hleft` line 404: the error 403:8 would be congr 1 — but \"No goals\" for congr means the goal was already closed before it ran?? The `:= by` — the calc step's goal... \n\nHmm — actually maybe the issue: the calc step 5's expected relation got FULLY proved by... no.\n\nAlternatively line 403 is `exact hleft` and congr 1 closed everything. Could congr 1 close `A + (B+C) = A' + (B+C)` completely? Its rfl-routine: tries to close subgoals by rfl/defeq — A = A' is NOT defeq... unless congr DIDN'T split (head match failed?) and fell back to trying the whole goal by rfl — fails — then... error would be \"congr failed\". Hmm.\n\nWait — actually — maybe the calc-step elaboration ORDER: the `:= by` proof is elaborated against the step's expected type `LHS = RHS`. LHS comes from the previous step's RHS (which is my parenthesized form). Hmm.\n\nLet me just look at what's on line 403.","signature":""},{"type":"text","text":"One error left at line 403. Checking what's there."},{"type":"tool_use","id":"Read_56","name":"Read","input":{"file_path":"D:\\Python\\Quantum\\research\\lean\\NguyenRH1\\NguyenRH1\\LiSideBounds.lean","offset":378,"limit":35},"extra_content":null}]