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← Session 35 — ii′-6-R: Lagarias 6.1 right-tail re-proof (E-032/D-073)

#2157 assistant 2026-08-26 08:09:32.781 UTC · 895→1248 tok open ⤢
thinking (2350 chars)
Now down to hwid's actual issue. The leftover goal after `rw [hw1]; field_simp [hs0]; ring` at 805–808: `⊢ ↑(√↑n * 2) + ↑t * I = 1 + ↑t * I + ↑(-1 + √↑n * 2)` So `ring` normalized but didn't close: LHS `↑(√↑n·2) + ↑t·I`, RHS `1 + ↑t·I + ↑(−1+√↑n·2)`. The identity: ↑(√↑n·2) = 1 + ↑(−1+√↑n·2) ⟺ √↑n·2 = 1 + (−1+√↑n·2) ✓ — but ring treats `↑(√↑n·2)` and `↑(−1+√↑n·2)` as ATOMS (casts) and can't cancel without push_cast!! The `field_simp [hs0]` turned the division equation into this and `ring` can't push the casts. FIX: `push_cast; ring` after field_simp? — or replace ring with `push_cast; ring`... The goal: `↑(√↑n·2) + ↑t·I = 1 + ↑t·I + ↑(−1+√↑n·2)` — push_cast normalizes `↑(−1+√↑n·2)` → `−1 + ↑√↑n·2`?? — push_cast pushes the cast through the arithmetic: ↑(−1+√↑n·2) = −1+↑(√↑n·2)... — then `↑(√↑n·2) + ↑t·I = 1 + ↑t·I + (−1 + ↑(√↑n·2))` ⟺ equal ✓ ring closes ✓. So: `field_simp [hs0]; push_cast; ring` — but if push_cast does nothing (the earlier linter said it did nothing at 474) — then ring... Let me think again: the goal has `↑(-1 + √↑n * 2)` — a cast of a REAL EXPRESSION (−1+√↑n·2) — push_cast normalizes it to `↑(√↑n·2) − 1` (map_sub) ✓ then ring closes ✓. So: ``` rw [hw1] field_simp [hs0] push_cast ring ``` If field_simp closes, the rest errors... — no, field_simp didn't close (left the goal shown) — so push_cast; ring needed ✓. Hmm wait — actually the issue might be simpler: field_simp changed the goal to `↑(√↑n·2) + ↑t·I = 1 + ↑t·I + ↑(−1+√↑n·2)` — this is a TRUE complex identity needing cast arithmetic. Alternative finish: prove hwid via a cleaner algebraic route: ``` have hwid : ... := by rw [hw1] rw [div_eq_iff hs0] push_cast ring ``` div_eq_iff (hb : b ≠ 0) : a / b = c ↔ a = c * b — the goal after rw [hw1]: `(↑(2√↑n)+↑t·I)/(↑(2√↑n−1)+↑t·I) = 1 + 1/(↑(2√↑n−1)+↑t·I)` — hmm — div_eq_iff needs the RHS to be `c` — the RHS is `1 + 1/(w−1)` — not a plain `c`. Use `eq_div_iff hs0`?? — `eq_div_iff (hc : c ≠ 0) : a = b / c ↔ a * c = b`?? — the goal is `w/(w−1) = 1 + 1/(w−1)` — both sides have divisions. Multiply out first: `div_add_div (w) (1) hs0 hs0`?? — messy. Simplest: `field_simp [hs0]; push_cast; ring` — try it. If field_simp closes the goal entirely, push_cast errors — the error showed field_simp did NOT close (left the cast goal) ✓ so push_cast; ring is the right finish.
The leftover is a cast-arithmetic identity — `field_simp` needs `push_cast` before `ring` here.
tool: Edit
input
{
  "file_path": "D:\\Python\\Quantum\\research\\lean\\NguyenRH1\\NguyenRH1\\LiDogLeg.lean",
  "old_string": "  have hwid : (((2 * Real.sqrt (n : \u211d)) : \u211d) + t * Complex.I) /\n      ((((2 * Real.sqrt (n : \u211d)) : \u211d) + t * Complex.I) - 1) =\n      1 + 1 / (((2 * Real.sqrt (n : \u211d) - 1) : \u211d) + t * Complex.I) := by\n    rw [hw1]\n    field_simp [hs0]\n    ring",
  "new_string": "  have hwid : (((2 * Real.sqrt (n : \u211d)) : \u211d) + t * Complex.I) /\n      ((((2 * Real.sqrt (n : \u211d)) : \u211d) + t * Complex.I) - 1) =\n      1 + 1 / (((2 * Real.sqrt (n : \u211d) - 1) : \u211d) + t * Complex.I) := by\n    rw [hw1]\n    field_simp [hs0]\n    push_cast\n    ring"
}
raw content_json (database row)
[{"type":"thinking","thinking":"Now down to hwid's actual issue. The leftover goal after `rw [hw1]; field_simp [hs0]; ring` at 805–808:\n\n`⊢ ↑(√↑n * 2) + ↑t * I = 1 + ↑t * I + ↑(-1 + √↑n * 2)`\n\nSo `ring` normalized but didn't close: LHS `↑(√↑n·2) + ↑t·I`, RHS `1 + ↑t·I + ↑(−1+√↑n·2)`. The identity: ↑(√↑n·2) = 1 + ↑(−1+√↑n·2) ⟺ √↑n·2 = 1 + (−1+√↑n·2) ✓ — but ring treats `↑(√↑n·2)` and `↑(−1+√↑n·2)` as ATOMS (casts) and can't cancel without push_cast!! The `field_simp [hs0]` turned the division equation into this and `ring` can't push the casts. FIX: `push_cast; ring` after field_simp? — or replace ring with `push_cast; ring`... The goal: `↑(√↑n·2) + ↑t·I = 1 + ↑t·I + ↑(−1+√↑n·2)` — push_cast normalizes `↑(−1+√↑n·2)` → `−1 + ↑√↑n·2`?? — push_cast pushes the cast through the arithmetic: ↑(−1+√↑n·2) = −1+↑(√↑n·2)... — then `↑(√↑n·2) + ↑t·I = 1 + ↑t·I + (−1 + ↑(√↑n·2))` ⟺ equal ✓ ring closes ✓. So: `field_simp [hs0]; push_cast; ring` — but if push_cast does nothing (the earlier linter said it did nothing at 474) — then ring... Let me think again: the goal has `↑(-1 + √↑n * 2)` — a cast of a REAL EXPRESSION (−1+√↑n·2) — push_cast normalizes it to `↑(√↑n·2) − 1` (map_sub) ✓ then ring closes ✓. So:\n```\n    rw [hw1]\n    field_simp [hs0]\n    push_cast\n    ring\n```\nIf field_simp closes, the rest errors... — no, field_simp didn't close (left the goal shown) — so push_cast; ring needed ✓.\n\nHmm wait — actually the issue might be simpler: field_simp changed the goal to `↑(√↑n·2) + ↑t·I = 1 + ↑t·I + ↑(−1+√↑n·2)` — this is a TRUE complex identity needing cast arithmetic. Alternative finish: prove hwid via a cleaner algebraic route:\n```\n  have hwid : ... := by\n    rw [hw1]\n    rw [div_eq_iff hs0]\n    push_cast\n    ring\n```\ndiv_eq_iff (hb : b ≠ 0) : a / b = c ↔ a = c * b — the goal after rw [hw1]: `(↑(2√↑n)+↑t·I)/(↑(2√↑n−1)+↑t·I) = 1 + 1/(↑(2√↑n−1)+↑t·I)` — hmm — div_eq_iff needs the RHS to be `c` — the RHS is `1 + 1/(w−1)` — not a plain `c`. Use `eq_div_iff hs0`?? — `eq_div_iff (hc : c ≠ 0) : a = b / c ↔ a * c = b`?? — the goal is `w/(w−1) = 1 + 1/(w−1)` — both sides have divisions. Multiply out first: `div_add_div (w) (1) hs0 hs0`?? — messy.\n\nSimplest: `field_simp [hs0]; push_cast; ring` — try it. If field_simp closes the goal entirely, push_cast errors — the error showed field_simp did NOT close (left the cast goal) ✓ so push_cast; ring is the right finish.","signature":""},{"type":"text","text":"The leftover is a cast-arithmetic identity — `field_simp` needs `push_cast` before `ring` here."},{"type":"tool_use","id":"Edit_352","name":"Edit","input":{"file_path":"D:\\Python\\Quantum\\research\\lean\\NguyenRH1\\NguyenRH1\\LiDogLeg.lean","old_string":"  have hwid : (((2 * Real.sqrt (n : ℝ)) : ℝ) + t * Complex.I) /\n      ((((2 * Real.sqrt (n : ℝ)) : ℝ) + t * Complex.I) - 1) =\n      1 + 1 / (((2 * Real.sqrt (n : ℝ) - 1) : ℝ) + t * Complex.I) := by\n    rw [hw1]\n    field_simp [hs0]\n    ring","new_string":"  have hwid : (((2 * Real.sqrt (n : ℝ)) : ℝ) + t * Complex.I) /\n      ((((2 * Real.sqrt (n : ℝ)) : ℝ) + t * Complex.I) - 1) =\n      1 + 1 / (((2 * Real.sqrt (n : ℝ) - 1) : ℝ) + t * Complex.I) := by\n    rw [hw1]\n    field_simp [hs0]\n    push_cast\n    ring"},"extra_content":null}]