← Session 21 — Tier ii′ planning + launch: close SfBoundProp in Lean (D-064)
thinking (7577 chars)
Down to three errors:
1. Line 144: `mul_le_mul_of_nonneg_left hb2 (by positivity)` — positivity picked `z.re` (hzre0) instead of 1/‖z‖! Because positivity proves `0 ≤ 1/‖z‖` but the mul_le_mul_of_nonneg_left's second argument needs to be 0 ≤ (1/‖z‖) — positivity should do that... but the error shows it used hzre0 (z.re). Weird — oh I see: the error is that `mul_le_mul_of_nonneg_left hb2 hzre0` was elaborated with `hzre0` — but I wrote `(by positivity)`. Hmm no — the error says "has type z.re * ... ≤ z.re * ..." — so Lean unified the outer factor as z.re?? That means hb2's statement had z.re in it?? No — the error might be misdirected: `(by positivity)` for `0 ≤ 1/‖z‖`... Actually looking again: `mul_le_mul_of_nonneg_left hb2 hzre0` — the term shows hzre0 — but I wrote (by positivity). Unless the file has a different spot. OH WAIT — I see: this is error at line 144 — hb3's definition. `mul_le_mul_of_nonneg_left hb2 (by positivity)` — the `by positivity` attempt — hmm, but the displayed term has hzre0. That's bizarre... OH — I bet the issue: hb2 : M^(n-1) * (n*(n−1)/2) ≤ 2*(n²/2), and hb3's target: (1/‖z‖)*M^(n-1)*(n*(n−1)/2) ≤ (1/‖z‖)*(2*(n²/2)). Note the ASSOCIATION: (1/‖z‖) * M^(n−1) * (...) — Lean parses as ((1/‖z‖) * M^(n−1)) * (...) — so the "left factor" is ((1/‖z‖)*M^(n−1)) not (1/‖z‖). mul_le_mul_of_nonneg_left : b ≤ c → 0 ≤ a → a*b ≤ a*c — needs the target a*(M^(n−1)*(...)) vs a*(2*(n²/2)) — but the goal has ((1/‖z‖)*M^(n−1))*(...) — association mismatch! Fix: restate hb3's target with explicit parentheses: `(1/‖z‖) * (M^(n-1) * (n*(n-1)/2)) ≤ (1/‖z‖) * (2*(n^2/2))`. Or use mul_le_mul_of_nonneg_left hb2 (by positivity : (0:ℝ) ≤ 1/‖z‖) after converting association. Simplest: change hb3's statement to the parenthesized form and the subsequent `hb3.trans (by ring_nf)` — ring_nf handles the reassociation to n²/‖z‖ ✓.
Hmm wait, but the error display shows the elaborated term with z.re — that suggests `by positivity` synthesized 0 ≤ z.re?? That can't be — unless positivity picked the wrong goal... Actually the error message shows the INFERRED type of `mul_le_mul_of_nonneg_left hb2 hzre0` — where did hzre0 come from? Maybe Lean's elaboration of `(by positivity)` produced hzre0?? No... OH WAIT — I see it now: the error is at 144:12, and it says the term `mul_le_mul_of_nonneg_left hb2 hzre0` — hzre0 must be what `by positivity` returned?! positivity wouldn't return hzre0 for 0 ≤ 1/‖z‖... unless the expected type was different. Hmm — whatever the cause, the association issue is real: hb2 has form `A * B ≤ C` where A = M^(n−1), B = (n(n−1)/2); the target needs a*(A*B) ≤ a*C — with a = 1/‖z‖. But the displayed error term is `z.re * (M^(n-1) * (↑n*(↑n−1)/2)) ≤ z.re * (2*(↑n^2/2))` — the z.re! So Lean parsed the multiplier as z.re — meaning my hb3 statement in the file might actually have z.re?? Let me look at what I wrote: `((1 : ℝ) / ‖z‖) * M ^ (n - 1) * (n * (n - 1) / 2) ≤ (1 / ‖z‖) * (2 * (n ^ 2 / 2))` — hmm `(1 : ℝ)/‖z‖` — that's fine... wait, the error at 144:12 — let me count lines: 144 might be the hb3 line `mul_le_mul_of_nonneg_left hb2 (by positivity)`. The displayed mismatch: expected `1/‖z‖ * ...` got `z.re * ...`. So `by positivity` somehow proved `0 ≤ z.re`?? NO — actually: `mul_le_mul_of_nonneg_left` in recent Mathlib signature: `mul_le_mul_of_nonneg_left (h : b ≤ c) (ha : 0 ≤ a) : a * b ≤ a * c`. Given hb2 and a goal `1/‖z‖ * (M^.. * ...) ≤ 1/‖z‖ * (2*(n²/2))`, elaboration unifies a := 1/‖z‖, b := M^(n−1)*(...), c := 2*(n²/2). The second arg (by positivity) proves 0 ≤ 1/‖z‖ ✓. That should work — UNLESS positivity proved something else... The error message is strange. The displayed type of the term has z.re — could `by positivity` for `0 ≤ 1/‖z‖`... no. OK whatever — maybe the issue is hb3's LHS association: `(1/‖z‖) * M^(n-1) * X` parses as `((1/‖z‖) * M^(n-1)) * X` — then mul_le_mul_of_nonneg_left hb2 gives `a * (M^(n-1)*X') ≤ a * (...)` with b := M^(n−1)*X' — but the goal's form is ((1/‖z‖)*M^(n−1))*X — these don't match (different association), so Lean tried to unify b with X and a with (1/‖z‖)*M^(n−1)... and (by positivity) for 0 ≤ (1/‖z‖)*M^(n−1)... but the error shows z.re — I can't fully explain, but the fix is clear: parenthesize. Let me also double check by positivity could return hzre0: positivity extension might close `0 ≤ z.re`? The expected type was `0 ≤ ?a` — with ?a unified to z.re?? — meaning unification set a := z.re: that happens if the GOAL had `z.re * ...` — did I write z.re anywhere near hb3? NO... unless the error line numbering is off and this is about hA: hA's proof has `apply mul_le_mul_of_nonneg_left _ hn0.le; exact abs_le.mpr ⟨hzre0, hzre1⟩` — no.
Let me just look at the current file around line 144 to see what's actually there.
2. Line 147: `↑n * (z.re / normSq z) = ↑n * z.re / ‖z‖ ^ 2` — hre1's simp [hinv] left this: after rw [Complex.mul_re], simp [hinv] — need to push n into the division: n·(z.re/normSq z) = n·z.re/‖z‖²: rw [hinv, hnsq]?? The displayed remaining goal: ↑n * (z.re / normSq z) = ↑n * z.re / ‖z‖ ^ 2 — fix: rw [hnsq] then ring? or field_simp: `rw [hnsq]; ring`? Wait — the goal after simp [hinv]: ↑n*(z.re/normSq z) = ↑n*z.re/‖z‖²: rewrite normSq via hnsq: ↑n*(z.re/‖z‖²) = ↑n*z.re/‖z‖²: `rw [hnsq]; ring`? ring normalizes mul_div ✓. Let me make hre1's proof:
```
have hre1 : ((n : ℂ) * (1 / z)).re = n * z.re / ‖z‖ ^ 2 := by
have hinv : ((1 : ℂ) / z).re = z.re / ‖z‖ ^ 2 := by
rw [one_div, Complex.inv_re, hnsq]
rw [Complex.mul_re]
simp [hinv, hnsq]
ring
```
Hmm — after rw [Complex.mul_re]: goal (↑n).re * (1/z).re − (↑n).im * (1/z).im = ...: simp [hinv] should simplify (↑n).re → ↑n (Complex.natCast_re), (↑n).im → 0, (1/z).re → z.re/‖z‖² (hinv as simp)... the remaining goal shown is `↑n * (z.re / normSq z) = ↑n * z.re / ‖z‖ ^ 2` — so simp DID reduce to that point; add hnsq to the simp set and then `field_simp`/`ring`. With hnsq in simp: normSq z → ‖z‖²: goal: ↑n*(z.re/‖z‖²) = ↑n*z.re/‖z‖² — `mul_div` — rfl after ring_nf? simp [hinv, hnsq, mul_div] should close, or add `; ring_nf`.
3. Line 153: hfre's rw [Complex.add_re] — pattern (?z + ?w).re not found: the goal is `(1/z * (↑n + (S − ↑n))).re = ...` — the re of a PRODUCT (1/z * X), not a sum. I need to first rewrite the product as a sum: (1/z)*(n + (S−n)) = n*(1/z) + (S−n)/z — I removed that step! In this version I wrote:
```
have hfre : ... := by
rw [hf, hS, Complex.add_re]
```
hf : 1 − wⁿ = (1/z)*S; hS : S = n + (S−n): after rw [hf, hS]: goal ((1/z)*(↑n + (S − ↑n))).re — need to distribute first:
```
have hd : (1 / z) * ((n : ℂ) + (S - n)) = (n : ℂ) * (1 / z) + (S - n) / z := by
field_simp; ring
rw [hf, hS, hd, Complex.add_re, hre1]
```
Wait — careful: (1/z)*(n + X) = n*(1/z) + (S−n)/z: (1/z)*n = n*(1/z) ✓ and (1/z)*(S−n) = (S−n)/z ✓. field_simp + ring ✓.
Then after rw [..., Complex.add_re, hre1]: goal `↑n * z.re/‖z‖² + ((S−n)/z).re = ↑n * z.re/‖z‖² + ((S−n)/z).re`? — hfre's RHS: n * z.re / ‖z‖ ^ 2 + ((S - n) / z).re ✓ matches — rfl.
Hmm but earlier hfre had a `congr 1; rw [mul_comm, div_eq_mul_inv]; exact hre1` structure — the congr 1 split into two goals: ((1/z)*↑n... no wait. Let me rewrite hfre cleanly:
```
have hfre : (1 - w ^ n).re = n * z.re / ‖z‖ ^ 2 + ((S - n) / z).re := by
have hd : (1 / z) * ((n : ℂ) + (S - n)) = (n : ℂ) * (1 / z) + (S - n) / z := by
field_simp; ring
rw [hf, hS, hd, Complex.add_re, hre1]
```
The final: ((↑n)*(1/z)).re + ((S−n)/z).re = n·z.re/‖z‖² + ((S−n)/z).re — rw [hre1] rewrites ((n:ℂ)*(1/z)).re ✓ → n·z.re/‖z‖² — goal becomes rfl ✓ (rw closes).
Let me apply these three fixes.
Three fixes: hb3 association, hre1's normSq rewrite, and hfre's missing distribution step.
tool: Edit
input
{
"file_path": "D:\\Python\\Quantum\\research\\lean\\NguyenRH1\\Scratch.lean",
"old_string": " have hb3 : ((1 : \u211d) / \u2016z\u2016) * M ^ (n - 1) * (n * (n - 1) / 2)\n \u2264 (1 / \u2016z\u2016) * (2 * (n ^ 2 / 2)) :=\n mul_le_mul_of_nonneg_left hb2 (by positivity)\n exact hb3.trans (by ring_nf)",
"new_string": " have hb3 : ((1 : \u211d) / \u2016z\u2016) * (M ^ (n - 1) * (n * (n - 1) / 2))\n \u2264 (1 / \u2016z\u2016) * (2 * (n ^ 2 / 2)) :=\n mul_le_mul_of_nonneg_left hb2 (by positivity)\n exact hb3.trans (by ring_nf)"
}
raw content_json (database row)
[{"type":"thinking","thinking":"Down to three errors:\n\n1. Line 144: `mul_le_mul_of_nonneg_left hb2 (by positivity)` — positivity picked `z.re` (hzre0) instead of 1/‖z‖! Because positivity proves `0 ≤ 1/‖z‖` but the mul_le_mul_of_nonneg_left's second argument needs to be 0 ≤ (1/‖z‖) — positivity should do that... but the error shows it used hzre0 (z.re). Weird — oh I see: the error is that `mul_le_mul_of_nonneg_left hb2 hzre0` was elaborated with `hzre0` — but I wrote `(by positivity)`. Hmm no — the error says \"has type z.re * ... ≤ z.re * ...\" — so Lean unified the outer factor as z.re?? That means hb2's statement had z.re in it?? No — the error might be misdirected: `(by positivity)` for `0 ≤ 1/‖z‖`... Actually looking again: `mul_le_mul_of_nonneg_left hb2 hzre0` — the term shows hzre0 — but I wrote (by positivity). Unless the file has a different spot. OH WAIT — I see: this is error at line 144 — hb3's definition. `mul_le_mul_of_nonneg_left hb2 (by positivity)` — the `by positivity` attempt — hmm, but the displayed term has hzre0. That's bizarre... OH — I bet the issue: hb2 : M^(n-1) * (n*(n−1)/2) ≤ 2*(n²/2), and hb3's target: (1/‖z‖)*M^(n-1)*(n*(n−1)/2) ≤ (1/‖z‖)*(2*(n²/2)). Note the ASSOCIATION: (1/‖z‖) * M^(n−1) * (...) — Lean parses as ((1/‖z‖) * M^(n−1)) * (...) — so the \"left factor\" is ((1/‖z‖)*M^(n−1)) not (1/‖z‖). mul_le_mul_of_nonneg_left : b ≤ c → 0 ≤ a → a*b ≤ a*c — needs the target a*(M^(n−1)*(...)) vs a*(2*(n²/2)) — but the goal has ((1/‖z‖)*M^(n−1))*(...) — association mismatch! Fix: restate hb3's target with explicit parentheses: `(1/‖z‖) * (M^(n-1) * (n*(n-1)/2)) ≤ (1/‖z‖) * (2*(n^2/2))`. Or use mul_le_mul_of_nonneg_left hb2 (by positivity : (0:ℝ) ≤ 1/‖z‖) after converting association. Simplest: change hb3's statement to the parenthesized form and the subsequent `hb3.trans (by ring_nf)` — ring_nf handles the reassociation to n²/‖z‖ ✓.\n\nHmm wait, but the error display shows the elaborated term with z.re — that suggests `by positivity` synthesized 0 ≤ z.re?? That can't be — unless positivity picked the wrong goal... Actually the error message shows the INFERRED type of `mul_le_mul_of_nonneg_left hb2 hzre0` — where did hzre0 come from? Maybe Lean's elaboration of `(by positivity)` produced hzre0?? No... OH WAIT — I see it now: the error is at 144:12, and it says the term `mul_le_mul_of_nonneg_left hb2 hzre0` — hzre0 must be what `by positivity` returned?! positivity wouldn't return hzre0 for 0 ≤ 1/‖z‖... unless the expected type was different. Hmm — whatever the cause, the association issue is real: hb2 has form `A * B ≤ C` where A = M^(n−1), B = (n(n−1)/2); the target needs a*(A*B) ≤ a*C — with a = 1/‖z‖. But the displayed error term is `z.re * (M^(n-1) * (↑n*(↑n−1)/2)) ≤ z.re * (2*(↑n^2/2))` — the z.re! So Lean parsed the multiplier as z.re — meaning my hb3 statement in the file might actually have z.re?? Let me look at what I wrote: `((1 : ℝ) / ‖z‖) * M ^ (n - 1) * (n * (n - 1) / 2) ≤ (1 / ‖z‖) * (2 * (n ^ 2 / 2))` — hmm `(1 : ℝ)/‖z‖` — that's fine... wait, the error at 144:12 — let me count lines: 144 might be the hb3 line `mul_le_mul_of_nonneg_left hb2 (by positivity)`. The displayed mismatch: expected `1/‖z‖ * ...` got `z.re * ...`. So `by positivity` somehow proved `0 ≤ z.re`?? NO — actually: `mul_le_mul_of_nonneg_left` in recent Mathlib signature: `mul_le_mul_of_nonneg_left (h : b ≤ c) (ha : 0 ≤ a) : a * b ≤ a * c`. Given hb2 and a goal `1/‖z‖ * (M^.. * ...) ≤ 1/‖z‖ * (2*(n²/2))`, elaboration unifies a := 1/‖z‖, b := M^(n−1)*(...), c := 2*(n²/2). The second arg (by positivity) proves 0 ≤ 1/‖z‖ ✓. That should work — UNLESS positivity proved something else... The error message is strange. The displayed type of the term has z.re — could `by positivity` for `0 ≤ 1/‖z‖`... no. OK whatever — maybe the issue is hb3's LHS association: `(1/‖z‖) * M^(n-1) * X` parses as `((1/‖z‖) * M^(n-1)) * X` — then mul_le_mul_of_nonneg_left hb2 gives `a * (M^(n-1)*X') ≤ a * (...)` with b := M^(n−1)*X' — but the goal's form is ((1/‖z‖)*M^(n−1))*X — these don't match (different association), so Lean tried to unify b with X and a with (1/‖z‖)*M^(n−1)... and (by positivity) for 0 ≤ (1/‖z‖)*M^(n−1)... but the error shows z.re — I can't fully explain, but the fix is clear: parenthesize. Let me also double check by positivity could return hzre0: positivity extension might close `0 ≤ z.re`? The expected type was `0 ≤ ?a` — with ?a unified to z.re?? — meaning unification set a := z.re: that happens if the GOAL had `z.re * ...` — did I write z.re anywhere near hb3? NO... unless the error line numbering is off and this is about hA: hA's proof has `apply mul_le_mul_of_nonneg_left _ hn0.le; exact abs_le.mpr ⟨hzre0, hzre1⟩` — no.\n\nLet me just look at the current file around line 144 to see what's actually there.\n\n2. Line 147: `↑n * (z.re / normSq z) = ↑n * z.re / ‖z‖ ^ 2` — hre1's simp [hinv] left this: after rw [Complex.mul_re], simp [hinv] — need to push n into the division: n·(z.re/normSq z) = n·z.re/‖z‖²: rw [hinv, hnsq]?? The displayed remaining goal: ↑n * (z.re / normSq z) = ↑n * z.re / ‖z‖ ^ 2 — fix: rw [hnsq] then ring? or field_simp: `rw [hnsq]; ring`? Wait — the goal after simp [hinv]: ↑n*(z.re/normSq z) = ↑n*z.re/‖z‖²: rewrite normSq via hnsq: ↑n*(z.re/‖z‖²) = ↑n*z.re/‖z‖²: `rw [hnsq]; ring`? ring normalizes mul_div ✓. Let me make hre1's proof:\n```\nhave hre1 : ((n : ℂ) * (1 / z)).re = n * z.re / ‖z‖ ^ 2 := by\n have hinv : ((1 : ℂ) / z).re = z.re / ‖z‖ ^ 2 := by\n rw [one_div, Complex.inv_re, hnsq]\n rw [Complex.mul_re]\n simp [hinv, hnsq]\n ring\n```\nHmm — after rw [Complex.mul_re]: goal (↑n).re * (1/z).re − (↑n).im * (1/z).im = ...: simp [hinv] should simplify (↑n).re → ↑n (Complex.natCast_re), (↑n).im → 0, (1/z).re → z.re/‖z‖² (hinv as simp)... the remaining goal shown is `↑n * (z.re / normSq z) = ↑n * z.re / ‖z‖ ^ 2` — so simp DID reduce to that point; add hnsq to the simp set and then `field_simp`/`ring`. With hnsq in simp: normSq z → ‖z‖²: goal: ↑n*(z.re/‖z‖²) = ↑n*z.re/‖z‖² — `mul_div` — rfl after ring_nf? simp [hinv, hnsq, mul_div] should close, or add `; ring_nf`.\n\n3. Line 153: hfre's rw [Complex.add_re] — pattern (?z + ?w).re not found: the goal is `(1/z * (↑n + (S − ↑n))).re = ...` — the re of a PRODUCT (1/z * X), not a sum. I need to first rewrite the product as a sum: (1/z)*(n + (S−n)) = n*(1/z) + (S−n)/z — I removed that step! In this version I wrote:\n```\nhave hfre : ... := by\n rw [hf, hS, Complex.add_re]\n```\nhf : 1 − wⁿ = (1/z)*S; hS : S = n + (S−n): after rw [hf, hS]: goal ((1/z)*(↑n + (S − ↑n))).re — need to distribute first:\n```\nhave hd : (1 / z) * ((n : ℂ) + (S - n)) = (n : ℂ) * (1 / z) + (S - n) / z := by\n field_simp; ring\nrw [hf, hS, hd, Complex.add_re, hre1]\n```\nWait — careful: (1/z)*(n + X) = n*(1/z) + (S−n)/z: (1/z)*n = n*(1/z) ✓ and (1/z)*(S−n) = (S−n)/z ✓. field_simp + ring ✓.\n\nThen after rw [..., Complex.add_re, hre1]: goal `↑n * z.re/‖z‖² + ((S−n)/z).re = ↑n * z.re/‖z‖² + ((S−n)/z).re`? — hfre's RHS: n * z.re / ‖z‖ ^ 2 + ((S - n) / z).re ✓ matches — rfl.\n\nHmm but earlier hfre had a `congr 1; rw [mul_comm, div_eq_mul_inv]; exact hre1` structure — the congr 1 split into two goals: ((1/z)*↑n... no wait. Let me rewrite hfre cleanly:\n```\nhave hfre : (1 - w ^ n).re = n * z.re / ‖z‖ ^ 2 + ((S - n) / z).re := by\n have hd : (1 / z) * ((n : ℂ) + (S - n)) = (n : ℂ) * (1 / z) + (S - n) / z := by\n field_simp; ring\n rw [hf, hS, hd, Complex.add_re, hre1]\n```\nThe final: ((↑n)*(1/z)).re + ((S−n)/z).re = n·z.re/‖z‖² + ((S−n)/z).re — rw [hre1] rewrites ((n:ℂ)*(1/z)).re ✓ → n·z.re/‖z‖² — goal becomes rfl ✓ (rw closes).\n\nLet me apply these three fixes.","signature":""},{"type":"text","text":"Three fixes: hb3 association, hre1's normSq rewrite, and hfre's missing distribution step."},{"type":"tool_use","id":"Edit_108","name":"Edit","input":{"file_path":"D:\\Python\\Quantum\\research\\lean\\NguyenRH1\\Scratch.lean","old_string":" have hb3 : ((1 : ℝ) / ‖z‖) * M ^ (n - 1) * (n * (n - 1) / 2)\n ≤ (1 / ‖z‖) * (2 * (n ^ 2 / 2)) :=\n mul_le_mul_of_nonneg_left hb2 (by positivity)\n exact hb3.trans (by ring_nf)","new_string":" have hb3 : ((1 : ℝ) / ‖z‖) * (M ^ (n - 1) * (n * (n - 1) / 2))\n ≤ (1 / ‖z‖) * (2 * (n ^ 2 / 2)) :=\n mul_le_mul_of_nonneg_left hb2 (by positivity)\n exact hb3.trans (by ring_nf)"},"extra_content":null}]