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putnam_2007_a1
abbrev putnam_2007_a1_solution : Set ℝ := sorry -- {2 / 3, 3 / 2, (13 + √601) / 12, (13 - √601) / 12} /-- Find all values of $\alpha$ for which the curves $y = \alpha*x^2 + \alpha*x + 1/24$ and $x = \alpha*y^2 + \alpha*y + 1/24$ are tangent to each other. -/ theorem putnam_2007_a1 (P : (ℝ β†’ ℝ) β†’ Prop) (P_def :...
dc281f82829d463e
putnam_2017_a1
abbrev putnam_2017_a1_solution : Set β„€ := sorry -- {x : β„€ | x > 0 ∧ (x = 1 ∨ 5 ∣ x)} /-- Let $S$ be the smallest set of positive integers such that (a) $2$ is in $S$, (b) $n$ is in $S$ whenever $n^2$ is in $S$, and (c) $(n+5)^2$ is in $S$ whenever $n$ is in $S$. Which positive integers are not in $S$?. -/ theorem putna...
71bf451d20ae8bbc
putnam_1970_a4
theorem putnam_1970_a4 (x : β„• β†’ ℝ) (hxlim : Tendsto (fun n => x (n+2) - x n) atTop (𝓝 0)) : Tendsto (fun n => (x (n+1) - x (n))/(n+1)) atTop (𝓝 0) := sorry
2f3009b9e8fe511c
putnam_2018_b2
theorem putnam_2018_b2 (n : β„•) (hn : n > 0) (f : β„• β†’ β„‚ β†’ β„‚) (hf : βˆ€ z : β„‚, f n z = βˆ‘ i in Finset.range n, (n - i) * z^i) : βˆ€ z : β„‚, β€–zβ€– ≀ 1 β†’ f n z β‰  0 := sorry
855548fadff25ed1
putnam_2008_b2
abbrev putnam_2008_b2_solution : ℝ := sorry -- -1 /-- Let $F_0(x)=\ln x$. For $n \geq 0$ and $x>0$, let $F_{n+1}(x)=\int_0^x F_n(t)\,dt$. Evaluate $\lim_{n \to \infty} \frac{n!F_n(1)}{\ln n}$. -/ theorem putnam_2008_b2 (F : β„• β†’ ℝ β†’ ℝ) (hF0 : βˆ€ x : ℝ, F 0 x = Real.log x) (hFn : βˆ€ n : β„•, βˆ€ x > 0, F (n + 1) x = ∫ t in Set...
4b0014f08d8ea741
putnam_1992_a1
theorem putnam_1992_a1 (f : β„€ β†’ β„€) : (f = fun n ↦ 1 - n) ↔ (βˆ€ n : β„€, f (f n) = n) ∧ (βˆ€ n : β„€, f (f (n + 2) + 2) = n) ∧ (f 0 = 1) := sorry
198846b5aa1a01eb
putnam_1978_b3
theorem putnam_1978_b3 (P : β„•+ β†’ Polynomial ℝ) (hP1 : P 1 = 1 + X) (hP2 : P 2 = 1 + 2 * X) (hPodd : βˆ€ n, P (2 * n + 1) = P (2 * n) + C ((n : ℝ) + 1) * X * P (2 * n - 1)) (hPeven : βˆ€ n, P (2 * n + 2) = P (2 * n + 1) + C ((n : ℝ) + 1) * X * P (2 * n)) (a : β„•+ β†’ ℝ) (haroot : βˆ€ n, (P n).eval (a n) = 0) (haub : βˆ€ n, βˆ€ x, (P...
62e406761e8d5e3d
putnam_1995_a5
abbrev putnam_1995_a5_solution : Prop := sorry -- True /-- Let $x_{1},x_{2},\dots,x_{n}$ be differentiable (real-valued) functions of a single variable $f$ which satisfy \begin{align*} \frac{dx_{1}}{dt} &= a_{11}x_{1} + a_{12}x_{2} + \cdots + a_{1n}x_{n} \ \frac{dx_{2}}{dt} &= a_{21}x_{1} + a_{22}x_{2} + \cdots + a_{2n...
f7b0a2cf562e84c9
putnam_1985_a5
abbrev putnam_1985_a5_solution : Set β„• := sorry -- {3, 4, 7, 8} /-- Let $I_m = \int_0^{2\pi} \cos(x)\cos(2x)\cdots \cos(mx)\,dx$. For which integers $m$, $1 \leq m \leq 10$ is $I_m \neq 0$? -/ theorem putnam_1985_a5 (I : β„• β†’ ℝ) (hI : I = fun (m : β„•) ↦ ∫ x in (0)..(2 * Real.pi), ∏ k in Finset.Icc 1 m, cos (k * x...
ef7a41ef54fc02ed
putnam_2000_a5
theorem putnam_2000_a5 (r : ℝ) (z : EuclideanSpace ℝ (Fin 2)) (p : Fin 3 β†’ (EuclideanSpace ℝ (Fin 2))) (rpos : r > 0) (pdiff : βˆ€ n m, (n β‰  m) β†’ (p n β‰  p m)) (pint : βˆ€ n i, p n i = round (p n i)) (pcirc : βˆ€ n, p n ∈ Metric.sphere z r) : βˆƒ n m, (n β‰  m) ∧ (dist (p n) (p m) β‰₯ r ^ ((1 : ℝ) / 3)) := sorry
ef7fb266130f62be
putnam_2010_a5
theorem putnam_2010_a5 (G : Type*) [Group G] (i : G β†ͺ (Fin 3 β†’ ℝ)) (h : βˆ€ a b, (i a) ×₃ (i b) = i (a * b) ∨ (i a) ×₃ (i b) = 0) (a b : G) : (i a) ×₃ (i b) = 0 := sorry
4d71dcea75a93105
putnam_2022_b1
theorem putnam_2022_b1 (P : Polynomial β„€) (b : β„• β†’ ℝ) (Pconst : P.coeff 0 = 0) (Podd : Odd (P.coeff 1)) (hB : βˆ€ x : ℝ, HasSum (fun i => b i * x ^ i) (Real.exp (aeval x P))) : βˆ€ k : β„•, b k β‰  0 := sorry
eaa4336414551d9a
putnam_2013_a3
theorem putnam_2013_a3 (n : β„•) (a : Set.Icc 0 n β†’ ℝ) (x : ℝ) (hx : 0 < x ∧ x < 1) (hsum : (βˆ‘ i : Set.Icc 0 n, a i / (1 - x ^ (i.1 + 1))) = 0) : βˆƒ y : ℝ, 0 < y ∧ y < 1 ∧ (βˆ‘ i : Set.Icc 0 n, a i * y ^ i.1) = 0 := sorry
c0cb05f1ff5f150f
putnam_2003_a3
abbrev putnam_2003_a3_solution : ℝ := sorry -- 2 * Real.sqrt 2 - 1 /-- Find the minimum value of $|\sin x+\cos x+\tan x+\cot x+\sec x+\csc x|$ for real numbers $x$. -/ theorem putnam_2003_a3 (f : ℝ β†’ ℝ) (hf : βˆ€ x : ℝ, f x = |Real.sin x + Real.cos x + Real.tan x + 1 / Real.tan x + 1 / Real.cos x + 1 / Real.sin x...
866efe559bcc093d
putnam_1974_a6
abbrev putnam_1974_a6_solution : β„• := sorry -- 25 /-- Given $n$, let $k(n)$ be the minimal degree of any monic integral polynomial $f$ such that the value of $f(x)$ is divisible by $n$ for every integer $x$. Find the value of $k(1000000)$. -/ theorem putnam_1974_a6 (hdivnallx : Polynomial β„€ β†’ Prop) (hdivnallx_def : hdi...
c7007e4f9de05873
putnam_1964_a6
theorem putnam_1964_a6 (S : Finset ℝ) (pairs : Set (ℝ Γ— ℝ)) (hpairs : pairs = {(a, b) | (a ∈ S) ∧ (b ∈ S) ∧ (a < b)}) (distance : ℝ Γ— ℝ β†’ ℝ) (hdistance : distance = fun (a, b) ↦ b - a) (hrepdist : βˆ€ p ∈ pairs, (βˆƒ m ∈ pairs, distance m > distance p) β†’ βˆƒ q ∈ pairs, q β‰  p ∧ distance p = distance q) : (βˆ€ p q : pairs, q β‰  p...
f217b6a03ce6bac2
putnam_1986_a3
abbrev putnam_1986_a3_solution : ℝ := sorry -- Real.pi / 2 /-- Evaluate $\sum_{n=0}^\infty \mathrm{Arccot}(n^2+n+1)$, where $\mathrm{Arccot}\,t$ for $t \geq 0$ denotes the number $\theta$ in the interval $0 < \theta \leq \pi/2$ with $\cot \theta = t$. -/ theorem putnam_1986_a3 (cot : ℝ β†’ ℝ) (fcot : cot = fun ΞΈ ↦ cos ΞΈ ...
e63058cdff236457
putnam_1996_a3
abbrev putnam_1996_a3_solution : Prop := sorry -- False /-- Suppose that each of 20 students has made a choice of anywhere from 0 to 6 courses from a total of 6 courses offered. Prove or disprove: there are 5 students and 2 courses such that all 5 have chosen both courses or all 5 have chosen neither course. -/ theorem...
2f88722f3195292b
putnam_1973_a2
abbrev putnam_1973_a2_solution : Prop := sorry -- True /-- Consider an infinite series whose $n$th term is given by $\pm \frac{1}{n}$, where the actual values of the $\pm$ signs repeat in blocks of $8$ (so the $\frac{1}{9}$ term has the same sign as the $\frac{1}{1}$ term, and so on). Call such a sequence balanced if e...
c51693e6eb479ee6
putnam_1963_a2
theorem putnam_1963_a2 (f : β„• β†’ β„•) (hfpos : βˆ€ n, f n > 0) (hfinc : StrictMonoOn f (Set.Ici 1)) (hf2 : f 2 = 2) (hfmn : βˆ€ m n, m > 0 β†’ n > 0 β†’ IsRelPrime m n β†’ f (m * n) = f m * f n) : βˆ€ n > 0, f n = n := sorry
8ce4a2f57fd2f72d
putnam_1987_a2
abbrev putnam_1987_a2_solution : β„• := sorry -- 1984 /-- The sequence of digits $123456789101112131415161718192021 \dots$ is obtained by writing the positive integers in order. If the $10^n$-th digit in this sequence occurs in the part of the sequence in which the $m$-digit numbers are placed, define $f(n)$ to be $m$. F...
54933b2da1297c4a
putnam_1988_b1
theorem putnam_1988_b1 : βˆ€ a β‰₯ 2, βˆ€ b β‰₯ 2, βˆƒ x y z : β„€, x > 0 ∧ y > 0 ∧ z > 0 ∧ a * b = x * y + x * z + y * z + 1 := sorry
87eff43764113c48
putnam_2020_b6
theorem putnam_2020_b6 (n : β„•) (npos : n > 0) : βˆ‘ k in Finset.Icc 1 n, ((-1) ^ Int.floor (k * (Real.sqrt 2 - 1)) : ℝ) β‰₯ 0 := sorry
c4f422b1777e8f8e
putnam_1998_b1
abbrev putnam_1998_b1_solution : ℝ := sorry -- 6 /-- Find the minimum value of \[\frac{(x+1/x)^6-(x^6+1/x^6)-2}{(x+1/x)^3+(x^3+1/x^3)}\] for $x>0$. -/ theorem putnam_1998_b1 : sInf {((x + 1/x)^6 - (x^6 + 1/x^6) - 2)/((x + 1/x)^3 + (x^3 + 1/x^3)) | x > (0 : ℝ)} = putnam_1998_b1_solution := sorry
f176c62769ce4d83
putnam_2002_a2
theorem putnam_2002_a2 (unit_sphere : Set (EuclideanSpace ℝ (Fin 3))) (hsphere : unit_sphere = sphere 0 1) (hemi : EuclideanSpace ℝ (Fin 3) β†’ Set (EuclideanSpace ℝ (Fin 3))) (hhemi : hemi = fun V ↦ {P : EuclideanSpace ℝ (Fin 3) | βŸͺP, V⟫_ℝ β‰₯ 0}) : (βˆ€ (S : Set (EuclideanSpace ℝ (Fin 3))), S βŠ† unit_sphere ∧ S.encard = 5 β†’...
152f16dbdcdf9d5b
putnam_2012_a2
theorem putnam_2012_a2 (S : Type*) [CommSemigroup S] (a b c : S) (hS : βˆ€ x y : S, βˆƒ z : S, x * z = y) (habc : a * c = b * c) : a = b := sorry
9c82af6e9122e750
putnam_1962_a3
theorem putnam_1962_a3 (A B C A' B' C' P Q R : EuclideanSpace ℝ (Fin 2)) (k : ℝ) (hk : k > 0) (hABC : Β¬Collinear ℝ {A, B, C}) (hA' : A' ∈ segment ℝ B C ∧ dist C A' / dist A' B = k) (hB' : B' ∈ segment ℝ C A ∧ dist A B' / dist B' C = k) (hC' : C' ∈ segment ℝ A B ∧ dist B C' / dist C' A = k) (hP : P ∈ segment ℝ B B' ∧ P ...
323992d1505ba6eb
putnam_1972_a3
abbrev putnam_1972_a3_solution : Set (ℝ β†’ ℝ) := sorry -- {f | βˆƒ A B : ℝ, βˆ€ x ∈ Set.Icc 0 1, f x = A * x + B} /-- We call a function $f$ from $[0,1]$ to the reals to be supercontinuous on $[0,1]$ if the Cesaro-limit exists for the sequence $f(x_1), f(x_2), f(x_3), \dots$ whenever it does for the sequence $x_1, x_2, x_3 ...
338a897dcbc74c58
putnam_2015_a6
theorem putnam_2015_a6 (n : β„•) (A B M : Matrix (Fin n) (Fin n) ℝ) (npos : n > 0) (hmul : A * M = M * B) (hpoly : Matrix.charpoly A = Matrix.charpoly B) : βˆ€ X : Matrix (Fin n) (Fin n) ℝ, (A - M * X).det = (B - X * M).det := sorry
065610d5c5c22e3f
putnam_1990_a6
abbrev putnam_1990_a6_solution : β„• := sorry -- 17711 /-- If $X$ is a finite set, let $|X|$ denote the number of elements in $X$. Call an ordered pair $(S,T)$ of subsets of $\{1,2,\dots,n\}$ \emph{admissible} if $s>|T|$ for each $s \in S$, and $t>|S|$ for each $t \in T$. How many admissible ordered pairs of subsets of $...
90045cb1da5a6106
putnam_1980_a6
abbrev putnam_1980_a6_solution : ℝ := sorry -- 1 / Real.exp 1 /-- Let $C$ be the class of all real valued continuously differentiable functions $f$ on the interval $0 \leq x \leq 1$ with $f(0)=0$ and $f(1)=1$. Determine the largest real number $u$ such that $u \leq \int_0^1|f'(x)-f(x)|\,dx$ for all $f$ in $C$. -/ theor...
5b4f35c7ea302eca
putnam_2009_b3
abbrev putnam_2009_b3_solution : Set β„€ := sorry -- {n : β„€ | βˆƒ k β‰₯ 1, n = 2 ^ k - 1} /-- Call a subset $S$ of $\{1, 2, \dots, n\}$ \emph{mediocre} if it has the following property: Whenever $a$ and $b$ are elements of $S$ whose average is an integer, that average is also an element of $S$. Let $A(n)$ be the number of me...
f1f6e2307105ff38
putnam_2019_b3
theorem putnam_2019_b3 (n : β„•) (hn : n > 0) (Q : Matrix (Fin n) (Fin n) ℝ) (hQ0 : βˆ€ i j : Fin n, i β‰  j β†’ dotProduct (Q i) (Q j) = 0 ∧ dotProduct (Qα΅€ i) (Qα΅€ j) = 0) (hQ1 : βˆ€ i : Fin n, dotProduct (Q i) (Q i) = 1 ∧ dotProduct (Qα΅€ i) (Qα΅€ i) = 1) (u : Matrix (Fin n) (Fin 1) ℝ) (hu : uα΅€*u = 1) (P : Matrix (Fin n) (Fin n) ℝ)...
003c3d6b7e4ae77e
putnam_1971_a5
abbrev putnam_1971_a5_solution : β„€ Γ— β„€ := sorry -- (11, 8) /-- After each play of a certain game of solitaire, the player receives either $a$ or $b$ points, where $a$ and $b$ are positive integers with $a > b$; scores accumulate from play to play. If there are $35$ unattainable scores, one of which is $58$, find $a$ an...
5cecbd61d48c2b4d
putnam_2024_b4
abbrev putnam_2024_b4_solution : ℝ := sorry --(1 - rexp (- 2))/2 /-- Let $n$ be a positive integer. Set $a_{n, 0} = 1$. For $k \geq 0$ choose an integer $m_{n, k}$ uniformly at random from the set $\{1, 2, \ldots, n\}$, and let $$a_{n, k+1} = \begin{cases} a_{n, k} + 1 & \text{if } m_{n, k} > a_{n, k} \\ a_{n, k} & \te...
535809caa3501e5b
putnam_1966_a1
theorem putnam_1966_a1 (f : β„€ β†’ β„€) (hf : f = fun n : β„€ => βˆ‘ m in Finset.Icc 0 n, (if Even m then m / 2 else (m - 1)/2)) : βˆ€ x y : β„€, x > 0 ∧ y > 0 ∧ x > y β†’ x * y = f (x + y) - f (x - y) := sorry
100412fdc6624f04
putnam_2011_a4
abbrev putnam_2011_a4_solution : Set β„• := sorry -- {n : β„• | Odd n} /-- For which positive integers $n$ is there an $n \times n$ matrix with integer entries such that every dot product of a row with itself is even, while every dot product of two different rows is odd? -/ theorem putnam_2011_a4 (nmat : β„• β†’ Prop) ...
c4c7db6f47109dce
putnam_1969_b2
abbrev putnam_1969_b2_solution : Prop := sorry -- False /-- Show that a finite group can not be the union of two of its proper subgroups. Does the statement remain true if 'two' is replaced by 'three'? -/ theorem putnam_1969_b2 (P : β„• β†’ Prop) (P_def : βˆ€ n, P n ↔ βˆ€ (G : Type) [Group G] [Finite G], βˆ€ H : Fi...
c184cff6254ac63c
putnam_1994_a4
theorem putnam_1994_a4 (A B : Matrix (Fin 2) (Fin 2) β„€) (ABinv : Nonempty (Invertible A) ∧ Nonempty (Invertible (A + B)) ∧ Nonempty (Invertible (A + 2 * B)) ∧ Nonempty (Invertible (A + 3 * B)) ∧ Nonempty (Invertible (A + 4 * B))) : Nonempty (Invertible (A + 5 * B)) := sorry
e4b40ea6b74370fd
putnam_1979_b2
abbrev putnam_1979_b2_solution : ℝ Γ— ℝ β†’ ℝ := sorry -- fun (a, b) => (Real.exp (-1))*(b^b/a^a)^(1/(b-a)) /-- If $0 < a < b$, find $$\lim_{t \to 0} \left( \int_{0}^{1}(bx + a(1-x))^t dx \right)^{\frac{1}{t}}$$ in terms of $a$ and $b$. -/ theorem putnam_1979_b2 : βˆ€ a b : ℝ, 0 < a ∧ a < b β†’ Tendsto (fun t : ℝ => (∫ x in I...
a92b461714bf5f5a
putnam_1972_b5
theorem putnam_1972_b5 (A B C D : EuclideanSpace ℝ (Fin 3)) (hnonplanar : Β¬Coplanar ℝ {A, B, C, D}) (hangles : ∠ A B C = ∠ C D A ∧ ∠ B C D = ∠ D A B) : dist A B = dist C D ∧ dist B C = dist D A := sorry
99f84dcd457b70ed
putnam_1962_b5
theorem putnam_1962_b5 (n : β„€) (ng1 : n > 1) : (3 * (n : ℝ) + 1) / (2 * n + 2) < βˆ‘ i : Finset.Icc 1 n, ((i : ℝ) / n) ^ (n : ℝ) ∧ βˆ‘ i : Finset.Icc 1 n, ((i : ℝ) / n) ^ (n : ℝ) < 2 := sorry
3b8b2ad457bdf985
putnam_2012_b4
abbrev putnam_2012_b4_solution : Prop := sorry -- True /-- Suppose that $a_0 = 1$ and that $a_{n+1} = a_n + e^{-a_n}$ for $n=0,1,2,\dots$. Does $a_n - \log n$ have a finite limit as $n \to \infty$? (Here $\log n = \log_e n = \ln n$.) -/ theorem putnam_2012_b4 (a : β„• β†’ ℝ) (ha0 : a 0 = 1) (han : βˆ€ n : β„•, a (n + 1) = a n ...
ce253d9604e7e3c5
putnam_1975_b1
abbrev putnam_1975_b1_solution : β„€ := sorry -- 7 /-- Let $H$ be a subgroup of the additive group of ordered pairs of integers under componentwise addition. If $H$ is generated by the elements $(3, 8)$, $(4, -1)$, and $(5, 4)$, then $H$ is also generated by two elements $(1, b)$ and $(0, a)$ for some integer $b$ and pos...
df643ba70c65f458
putnam_1965_b1
abbrev putnam_1965_b1_solution : ℝ := sorry -- 1 / 2 /-- Find $$\lim_{n \to \infty} \int_{0}^{1} \int_{0}^{1} \cdots \int_{0}^{1} \cos^2\left(\frac{\pi}{2n}(x_1 + x_2 + \cdots + x_n)\right) dx_1 dx_2 \cdots dx_n.$$ -/ theorem putnam_1965_b1 : Tendsto (fun n : β„• ↦ ∫ x in {x : Fin (n+1) β†’ ℝ | βˆ€ k : Fin (n+1), x k ∈ Set.I...
424ce1c7af19c406
putnam_1987_b4
abbrev putnam_1987_b4_solution : Prop Γ— ℝ Γ— Prop Γ— ℝ := sorry -- (True, -1, True, 0) /-- Let $(x_1,y_1) = (0.8, 0.6)$ and let $x_{n+1} = x_n \cos y_n - y_n \sin y_n$ and $y_{n+1}= x_n \sin y_n + y_n \cos y_n$ for $n=1,2,3,\dots$. For each of $\lim_{n\to \infty} x_n$ and $\lim_{n \to \infty} y_n$, prove that the limit e...
afc66948594fb538
putnam_1997_b4
theorem putnam_1997_b4 (a : β„• β†’ β„• β†’ β„€) (ha : βˆ€ m n, a m n = coeff ((1 + X + X ^ 2) ^ m) n) (k : β„•) : (βˆ‘ i in Finset.Iic ⌊2 * (k : β„š) / 3βŒ‹β‚Š, (-1) ^ i * a (k - i) i) ∈ Icc 0 1 := sorry
719e573780ea2a71
putnam_1979_a4
abbrev putnam_1979_a4_solution : Prop := sorry -- True /-- Let $A$ be a set of $2n$ points in the plane, $n$ colored red and $n$ colored blue, such that no three points in $A$ are collinear. Must there exist $n$ closed straight line segments, each connecting one red and one blue point in $A$, such that no two of the $n...
af9e3eced5a7be57
putnam_1994_b2
abbrev putnam_1994_b2_solution : Set ℝ := sorry -- {c : ℝ | c < 243 / 8} /-- For which real numbers $c$ is there a straight line that intersects the curve $x^4+9x^3+cx^2+9x+4$ in four distinct points? -/ theorem putnam_1994_b2 (c : ℝ) : (βˆƒ m b : ℝ, {x : ℝ | m * x + b = x ^ 4 + 9 * x ^ 3 + c * x ^ 2 + 9 * x + 4}...
2d51744f0dcd3b0f
putnam_1969_a4
theorem putnam_1969_a4 : Tendsto (fun n => βˆ‘ i in Finset.Icc (1 : β„€) n, (-1)^(i+1)*(i : ℝ)^(-i)) atTop (𝓝 (∫ x in Ioo (0 : ℝ) 1, x^x)) := sorry
1b44abb7a3d546e7
putnam_1984_b2
abbrev putnam_1984_b2_solution : ℝ := sorry -- 8 /-- Find the minimum value of $(u-v)^2+(\sqrt{2-u^2}-\frac{9}{v})^2$ for $0<u<\sqrt{2}$ and $v>0$. -/ theorem putnam_1984_b2 (f : ℝ β†’ ℝ β†’ ℝ) (hf : βˆ€ u v : ℝ, f u v = (u - v) ^ 2 + (Real.sqrt (2 - u ^ 2) - 9 / v) ^ 2) : IsLeast {y | βˆƒα΅‰ (u : Set.Ioo 0 √2) (v > ...
7c0ab9c8f0dd975a
putnam_2001_b2
abbrev putnam_2001_b2_solution : Set (ℝ Γ— ℝ) := sorry -- {((3 ^ ((1 : ℝ) / 5) + 1) / 2, (3 ^ ((1 : ℝ) / 5) - 1) / 2)} /-- Find all pairs of real numbers $(x,y)$ satisfying the system of equations \begin{align*} \frac{1}{x}+\frac{1}{2y}&=(x^2+3y^2)(3x^2+y^2) \\ \frac{1}{x}-\frac{1}{2y}&=2(y^4-x^4). \end{align*} -/ theor...
e94ea7031451eb3a
putnam_2011_b2
abbrev putnam_2011_b2_solution : Set β„• := sorry -- {2, 5} /-- Let $S$ be the set of all ordered triples $(p,q,r)$ of prime numbers for which at least one rational number $x$ satisfies $px^2+qx+r=0$. Which primes appear in seven or more elements of $S$? -/ theorem putnam_2011_b2 (S : Set (Fin 3 β†’ β„•)) (t : β„•) (hS :...
236b9e65124ae824
putnam_2023_a6
abbrev putnam_2023_a6_solution : Set β„• := sorry -- {n : β„• | 0 < n} /-- Alice and Bob play a game in which they take turns choosing integers from $1$ to $n$. Before any integers are chosen, Bob selects a goal of 'odd' or 'even'. On the first turn, Alice chooses one of the $n$ integers. On the second turn, Bob chooses on...
cd230851416cd5dd
putnam_2006_b6
abbrev putnam_2006_b6_solution : β„• β†’ ℝ := sorry -- fun k => ((k+1)/k)^k /-- Let $k$ be an integer greater than 1. Suppose $a_0 > 0$, and define \[ a_{n+1} = a_n + \frac{1}{\sqrt[k]{a_n}} \] for $n > 0$. Evaluate \[\lim_{n \to \infty} \frac{a_n^{k+1}}{n^k}.\] -/ theorem putnam_2006_b6 (k : β„•) (hk : k > 1) (a : β„• β†’ ℝ) (h...
5463d574e46b3040
putnam_2016_b6
abbrev putnam_2016_b6_solution : ℝ := sorry -- 1 /-- Evaluate $\sum_{k=1}^\infty \frac{(-1)^{k-1}}{k} \sum_{n=0}^\infty \frac{1}{k2^n+1}$. -/ theorem putnam_2016_b6 : βˆ‘' k : β„•, ((-1 : ℝ) ^ ((k + 1 : β„€) - 1) / (k + 1 : ℝ)) * βˆ‘' n : β„•, (1 : ℝ) / ((k + 1) * (2 ^ n) + 1) = putnam_2016_b6_solution := sorry
5d7fc8fd14d11d50
putnam_2024_a2
abbrev putnam_2024_a2_solution : Set ℝ[X] := sorry -- {s β€’ X + C a | (s : β„€Λ£) (a : ℝ)} /-- For which real polynomials $p$ is there a real polynomial $q$ such that $p(p(x)) - x = (p(x) - x)^2q(x)$ for all real $x$? -/ theorem putnam_2024_a2 : { p : Polynomial ℝ | βˆƒ (q : Polynomial ℝ), βˆ€ x, p.eval (p.eval x) - ...
237c86d43a7d5525
putnam_1971_b3
theorem putnam_1971_b3 (T : ℝ) (hT : T > 0) : MeasureTheory.volume {t : ℝ | t β‰₯ T ∧ Nat.floor t = 2 * (Nat.floor (t - T))} = 1 := sorry
6e3061a1afaee02d
putnam_2019_a5
abbrev putnam_2019_a5_solution : β„• β†’ β„• := sorry -- (fun p : β„• => (p - 1) / 2) /-- Let $p$ be an odd prime number, and let $\mathbb{F}_p$ denote the field of integers modulo $p$. Let $\mathbb{F}_p[x]$ be the ring of polynomials over $\mathbb{F}_p$, and let $q(x) \in \mathbb{F}_p[x]$ be given by $q(x)=\sum_{k=1}^{p-1} a_...
0ce3fd2e5f08ac75
putnam_2009_a5
abbrev putnam_2009_a5_solution : Prop := sorry -- False /-- Is there a finite abelian group $G$ such that the product of the orders of all its elements is 2^{2009}? -/ theorem putnam_2009_a5 : (βˆƒ (G : Type*) (_ : CommGroup G) (_ : Fintype G), ∏ g : G, orderOf g = 2^2009) ↔ putnam_2009_a5_solution := sorry
2db7be6af3abc680
putnam_1993_b6
theorem putnam_1993_b6 (S : Fin 3 β†’ β„•) (f : Fin 3 β†’ Fin 3 β†’ (Fin 3 β†’ β„•) β†’ (Fin 3 β†’ β„•)) (Spos : βˆ€ i : Fin 3, S i > 0) (hf : βˆ€ i j k : Fin 3, (i β‰  j ∧ i β‰  k ∧ j β‰  k) β†’ βˆ€ S' : Fin 3 β†’ β„•, if S' i ≀ S' j then ((f i j S') i = 2 * S' i ∧ (f i j S') j = S' j - S' i ∧ (f i j S') k = S' k) else (f i j S' = S')) : βˆƒ (Ss : β„• β†’ (Fi...
866f00cb4441d656
putnam_1983_b6
theorem putnam_1983_b6 (n : β„•) (npos : n > 0) (Ξ± : β„‚) (hΞ± : Ξ± ^ (2 ^ n + 1) - 1 = 0 ∧ Ξ± β‰  1) : (βˆƒ p q : Polynomial β„€, (aeval Ξ± p) ^ 2 + (aeval Ξ± q) ^ 2 = -1) := sorry
1b4edde165f51740
putnam_1977_b6
theorem putnam_1977_b6 {G : Type*} [Group G] (H : Subgroup G) (h : β„•) (h_def : h = Nat.card H) (a : G) (ha : βˆ€ x : H, (x*a)^3 = 1) (P : Set G) (hP : P = {g : G | βˆƒ xs : List H, (xs.length β‰₯ 1) ∧ g = (List.map (fun h : H => h*a) xs).prod}) : (Finite P) ∧ (P.ncard ≀ 3*h^2) := sorry
50e1fb025d0d1767
putnam_1967_b6
theorem putnam_1967_b6 (f : ℝ β†’ ℝ β†’ ℝ) (fdiff : (βˆ€ y : ℝ, Differentiable ℝ (fun x : ℝ => f x y)) ∧ (βˆ€ x : ℝ, Differentiable ℝ (fun y : ℝ => f x y))) (fbound : βˆ€ x y : ℝ, (x ^ 2 + y ^ 2 ≀ 1) β†’ |f x y| ≀ 1) : βˆƒ x0 y0 : ℝ, (x0 ^ 2 + y0 ^ 2 < 1) ∧ ((deriv (fun x : ℝ => f x y0) x0) ^ 2 + (deriv (fun y : ℝ => f x0 y) y0) ^ 2...
e3aefdc1bfcdb1cc
putnam_2010_b3
abbrev putnam_2010_b3_solution : Set β„• := sorry -- Ici 1005 /-- There are $2010$ boxes labeled $B_1, B_2, \dots, B_{2010}$, and $2010n$ balls have been distributed among them, for some positive integer $n$. You may redistribute the balls by a sequence of moves, each of which consists of choosing an $i$ and moving \emph...
147c81166d626394
putnam_2000_b3
theorem putnam_2000_b3 (N : β„•) (hN : N > 0) (a : Fin (N + 1) β†’ ℝ) (f : ℝ β†’ ℝ) (mult : (ℝ β†’ ℝ) β†’ ℝ β†’ β„•) (M : β„• β†’ β„•) (haN : a N β‰  0) (hf : βˆ€ t, f t = βˆ‘ j : Icc 1 N, a j * Real.sin (2 * Real.pi * j * t)) (hmult : βˆ€ g : ℝ β†’ ℝ, βˆ€ t : ℝ, (βˆƒ c : β„•, iteratedDeriv c g t β‰  0) β†’ (iteratedDeriv (mult g t) g t β‰  0 ∧...
b577e1f8143ebb95
putnam_1985_b3
theorem putnam_1985_b3 (a : β„• β†’ β„• β†’ β„•) (apos : βˆ€ m n : β„•, a m n > 0) (ha : βˆ€ k : β„•, k > 0 β†’ {(m, n) : β„• Γ— β„• | m > 0 ∧ n > 0 ∧ a m n = k}.encard = 8) : (βˆƒ m n, m > 0 ∧ n > 0 ∧ a m n > m * n) := sorry
c808f91c13e59d70
putnam_1968_a5
abbrev putnam_1968_a5_solution : ℝ := sorry -- 8 /-- Let $V$ be the set of all quadratic polynomials with real coefficients such that $|P(x)| \le 1$ for all $x \in [0, 1]$. Find the supremum of $|P'(0)|$ across all $P \in V$. -/ theorem putnam_1968_a5 (V : Set ℝ[X]) (V_def : V = {P : ℝ[X] | P.degree = 2 ∧ βˆ€ x ∈ Set.Icc...
790e33efe70b699a
putnam_1995_b3
abbrev putnam_1995_b3_solution : β„• β†’ β„€ := sorry -- fun n => if n = 1 then 45 else if n = 2 then 10 * 45^2 else 0 /-- To each positive integer with $n^{2}$ decimal digits, we associate the determinant of the matrix obtained by writing the digits in order across the rows. For example, for $n=2$, to the integer 8617 we as...
ba99130ed6d60ad3
putnam_1978_a5
theorem putnam_1978_a5 (n : β„•) (npos : n > 0) (a : Fin n β†’ ℝ) (ha : βˆ€ i : Fin n, a i ∈ Ioo 0 Real.pi) (ΞΌ : ℝ) (hΞΌ : ΞΌ = βˆ‘ i : Fin n, a i / n) : (∏ i : Fin n, sin (a i) / (a i) ≀ (sin ΞΌ / ΞΌ) ^ n) := sorry
25ef58852b4f0683
putnam_2008_a4
abbrev putnam_2008_a4_solution : Prop := sorry -- False /-- Define $f : \mathbb{R} \to \mathbb{R} by $f(x) = x$ if $x \leq e$ and $f(x) = x * f(\ln(x))$ if $x > e$. Does $\sum_{n=1}^{\infty} 1/(f(n))$ converge? -/ theorem putnam_2008_a4 (f : ℝ β†’ ℝ) (hf : f = fun x => if x ≀ Real.exp 1 then x else x * (f (Real.log x))) ...
83f1a3fde282cef1
putnam_2018_a4
theorem putnam_2018_a4 (m n : β„•) (a : β„• β†’ β„€) (G : Type*) [Group G] (g h : G) (mnpos : m > 0 ∧ n > 0) (mngcd : Nat.gcd m n = 1) (ha : βˆ€ k : Set.Icc 1 n, a k = Int.floor (m * k / (n : ℝ)) - Int.floor (m * ((k : β„€) - 1) / (n : ℝ))) (ghprod : ((List.Ico 1 (n + 1)).map (fun k : β„• => g * h ^ (a k))).prod = 1) : g * h = h * g...
93caf834393ad979
putnam_1970_b2
theorem putnam_1970_b2 (T : ℝ) (H : Polynomial ℝ) (hT : T > 0) (hH : H.degree ≀ 3) : (H.eval (-T / Real.sqrt 3) + H.eval (T / Real.sqrt 3))/2 = ⨍ t in Set.Icc (-T) T, H.eval t := sorry
f6f51125aa60956c
putnam_1973_b4
abbrev putnam_1973_b4_solution : ℝ β†’ ℝ := sorry -- (fun x => x) /-- Suppose $f$ is a function on $[0,1]$ with continuous derivative satisfying $0 < f'(x) \leq 1$ and $f 0 = 0$. Prove that $\left[\int_0^1 f(x) dx\right]]^2 \geq \int_0^1 (f(x))^3 dx$, and find an example where equality holds. -/ theorem putnam_1973_b4 (f...
dfba47b9632ab757
putnam_2004_b1
theorem putnam_2004_b1 (n : β„•) (P : Polynomial β„€) (r : β„š) (Pdeg : P.degree = n) (Preq0 : Polynomial.aeval r P = 0) : βˆ€ i ∈ Finset.range n, βˆƒ m : β„€, m = βˆ‘ j in Finset.range (i + 1), (P.coeff (n - j) * r ^ (i + 1 - j)) := sorry
3a756147ae0b27ae
putnam_2014_b1
abbrev putnam_2014_b1_solution : Set β„• := sorry -- {n : β„• | n > 0 ∧ Β¬βˆƒ a ∈ digits 10 n, a = 0} /-- A \emph{base $10$ over-expansion} of a positive integer $N$ is an expression of the form \[ N = d_k 10^k + d_{k-1} 10^{k-1} + \cdots + d_0 10^0 \] with $d_k \neq 0$ and $d_i \in \{0,1,2,\dots,10\}$ for all $i$. For instan...
c47a0b765c8f9bea
putnam_1991_b1
abbrev putnam_1991_b1_solution : Set β„€ := sorry -- {A : β„€ | βˆƒ x > 0, A = x ^ 2} /-- For each integer $n \geq 0$, let $S(n)=n-m^2$, where $m$ is the greatest integer with $m^2 \leq n$. Define a sequence $(a_k)_{k=0}^\infty$ by $a_0=A$ and $a_{k+1}=a_k+S(a_k)$ for $k \geq 0$. For what positive integers $A$ is this sequen...
f73f437026f54352
putnam_1981_b1
abbrev putnam_1981_b1_solution : ℝ := sorry -- -1 /-- Find the value of $$\lim_{n \rightarrow \infty} \frac{1}{n^5}\sum_{h=1}^{n}\sum_{k=1}^{n}(5h^4 - 18h^2k^2 + 5k^4).$$ -/ theorem putnam_1981_b1 (f : β„• β†’ ℝ) (hf : f = fun n : β„• => ((1 : ℝ)/n^5) * βˆ‘ h in Finset.Icc 1 n, βˆ‘ k in Finset.Icc 1 n, (5*(h : ℝ)^4 - 18*h^2*k^2 ...
a71d97e8349bd247
putnam_1996_b5
abbrev putnam_1996_b5_solution : β„• β†’ β„• := sorry -- (fun n : β„• ↦ 2 ^ ⌊(n + 2) / 2βŒ‹β‚Š + 2 ^ ⌊(n + 1) / 2βŒ‹β‚Š - 2) /-- Given a finite string $S$ of symbols $X$ and $O$, we write $\Delta(S)$ for the number of $X$'s in $S$ minus the number of $O$'s. For example, $\Delta(XOOXOOX)=-1$. We call a string $S$ \emph{balanced} if ev...
e1df119f03886b84
putnam_1986_b5
abbrev putnam_1986_b5_solution : Prop := sorry -- False /-- Let $f(x,y,z) = x^2+y^2+z^2+xyz$. Let $p(x,y,z), q(x,y,z)$, $r(x,y,z)$ be polynomials with real coefficients satisfying \[ f(p(x,y,z), q(x,y,z), r(x,y,z)) = f(x,y,z). \] Prove or disprove the assertion that the sequence $p,q,r$ consists of some permutation of ...
738f1ca15d93f5b0
putnam_2021_a1
abbrev putnam_2021_a1_solution : β„• := sorry -- 578 /-- A grasshopper starts at the origin in the coordinate plane and makes a sequence of hops. Each hop has length $5$, and after each hop the grasshopper is at a point whose coordinates are both integers; thus, there are $12$ possible locations for the grasshopper after...
ca24544a4a6e37cb
putnam_1989_a6
theorem putnam_1989_a6 (F : Type*) [Field F] [Fintype F] (hF : Fintype.card F = 2) (Ξ± : PowerSeries F) (hΞ± : βˆ€ n : β„•, let bin := [1] ++ (digits 2 n) ++ [1]; PowerSeries.coeff F n Ξ± = ite (βˆ€ i j : Fin bin.length, i < j β†’ bin.get i = 1 β†’ bin.get j = 1 β†’ (βˆ€ k, i < k β†’ k < j β†’ bin.get k = 0) β†’ Even ((j : β„•) - (i : β„•) - 1))...
60102e0097c302ac
putnam_1999_a6
theorem putnam_1999_a6 (a : β„€ β†’ ℝ) (ha1 : a 1 = 1) (ha2 : a 2 = 2) (ha3 : a 3 = 24) (hange4 : βˆ€ n : β„•, n β‰₯ 4 β†’ a n = (6 * (a (n - 1))^2 * (a (n - 3)) - 8 * (a (n - 1)) * (a (n - 2))^2)/(a (n - 2) * a (n - 3))) : βˆ€ n, n β‰₯ 1 β†’ (βˆƒ k : β„€, a n = k * n) := sorry
7b7b7483e31ccce5
putnam_2003_b5
theorem putnam_2003_b5 (A B C : EuclideanSpace ℝ (Fin 2)) (hABC : dist 0 A = 1 ∧ dist 0 B = 1 ∧ dist 0 C = 1 ∧ dist A B = dist A C ∧ dist A B = dist B C) : (βˆƒ f : ℝ β†’ ℝ, βˆ€ P : EuclideanSpace ℝ (Fin 2), dist 0 P < 1 β†’ βˆƒ X Y Z : EuclideanSpace ℝ (Fin 2), dist X Y = dist P A ∧ dist Y Z = dist P B ∧ dist X Z = dist P...
d67612cbd1a50204
putnam_2013_b5
theorem putnam_2013_b5 (n : β„•) (hn : n β‰₯ 1) (k : Set.Icc 1 n) (fiter : (Set.Icc 1 n β†’ Set.Icc 1 n) β†’ Prop) (hfiter : βˆ€ f, fiter f ↔ βˆ€ x : Set.Icc 1 n, βˆƒ j : β„•, f^[j] x ≀ k) : {f | fiter f}.encard = k * n ^ (n - 1) := sorry
6e6bc982302cf810
putnam_1964_b1
theorem putnam_1964_b1 (a b : β„• β†’ β„•) (h : βˆ€ n, 0 < a n) (h' : Summable fun n ↦ (1 : ℝ) / a n) (h'' : βˆ€ n, b n = {k | a k ≀ n}.ncard) : Tendsto (fun n ↦ (b n : ℝ) / n) atTop (𝓝 0) := sorry
fb0bc1a134118b01
putnam_1974_b1
abbrev putnam_1974_b1_solution : (Fin 5 β†’ EuclideanSpace ℝ (Fin 2)) β†’ Prop := sorry -- fun p ↦ βˆƒα΅‰ (B > 0) (o : Equiv.Perm (Fin 5)), βˆ€ i, dist (p (o i)) (p (o (i + 1))) = B /-- Prove that the optimal configuration of 5 (not necessarily distinct) points $p_1, \dots, p_5$ on the unit circle which maximizes the sum of the...
c01c5dff94976787
putnam_2003_b4
theorem putnam_2003_b4 (f : ℝ β†’ ℝ) (a b c d e : β„€) (r1 r2 r3 r4 : ℝ) (ane0 : a β‰  0) (hf1 : βˆ€ z, f z = a * z ^ 4 + b * z ^ 3 + c * z ^ 2 + d * z + e) (hf2 : βˆ€ z, f z = a * (z - r1) * (z - r2) * (z - r3) * (z - r4)) : (Β¬Irrational (r1 + r2) ∧ r1 + r2 β‰  r3 + r4) β†’ Β¬Irrational (r1 * r2) := sorry
d5cf5499f48b34b6
putnam_2013_b4
theorem putnam_2013_b4 (ΞΌ Var M : C(Icc (0 : ℝ) 1, ℝ) β†’ ℝ) (hΞΌ : βˆ€ f, ΞΌ f = ∫ x, f x) (hVar : βˆ€ f, Var f = ∫ x, (f x - ΞΌ f) ^ 2) (hM : βˆ€ f : C(Icc (0 : ℝ) 1, ℝ), IsGreatest (range <| abs ∘ f) (M f)) (f g : C(Icc (0 : ℝ) 1, ℝ)) : Var (f * g) ≀ 2 * Var f * (M g) ^ 2 + 2 * Var g * (M f) ^ 2 := sorr...
f5f67d0ea739aa89
putnam_1996_b4
abbrev putnam_1996_b4_solution : Prop := sorry -- False /-- For any square matrix $A$, we can define $\sin A$ by the usual power series: $\sin A=\sum_{n=0}^\infty \frac{(-1)^n}{(2n+1)!}A^{2n+1}$. Prove or disprove: there exists a $2 \times 2$ matrix $A$ with real entries such that $\sin A=\begin{pmatrix} 1 & 1996 \\ 0 ...
de47a3f260425db4
putnam_1986_b4
abbrev putnam_1986_b4_solution : Prop := sorry -- True /-- For a positive real number $r$, let $G(r)$ be the minimum value of $|r - \sqrt{m^2+2n^2}|$ for all integers $m$ and $n$. Prove or disprove the assertion that $\lim_{r\to \infty}G(r)$ exists and equals $0$. -/ theorem putnam_1986_b4 (G : ℝ β†’ ℝ) (hGeq : βˆ€ r : ℝ, ...
9e36e83a7dc5e6a3
putnam_1963_b5
theorem putnam_1963_b5 (a : β„€ β†’ ℝ) (haineq : βˆ€ n β‰₯ 1, βˆ€ k : β„€, (n ≀ k ∧ k ≀ 2 * n) β†’ (0 ≀ a k ∧ a k ≀ 100 * a n)) (haseries : βˆƒ S : ℝ, Tendsto (fun N : β„• => βˆ‘ n : Fin N, a n) atTop (𝓝 S)) : Tendsto (fun n : β„€ => n * a n) atTop (𝓝 0) := sorry
09cf1b8c3e6696a2
putnam_1970_b3
theorem putnam_1970_b3 (S : Set (ℝ Γ— ℝ)) (a b : ℝ) (hab : a < b) (hS : βˆ€ s ∈ S, s.1 ∈ Ioo a b) (hSclosed : IsClosed S) : IsClosed {y | βˆƒ x : ℝ, ⟨x,y⟩ ∈ S} := sorry
99a97c71dd42d43e
putnam_2017_b6
abbrev putnam_2017_b6_solution : β„• := sorry -- 2016! / 1953! - 63! * 2016 /-- Find the number of ordered $64$-tuples $(x_0,x_1,\dots,x_{63})$ such that $x_0,x_1,\dots,x_{63}$ are distinct elements of $\{1,2,\dots,2017\}$ and \[ x_0 + x_1 + 2x_2 + 3x_3 + \cdots + 63 x_{63} \] is divisible by 2017. -/ theorem putnam_2017...
6f5f334b1b225e1e
putnam_2007_b6
theorem putnam_2007_b6 (f : β„• β†’ β„•) (hf : f = fun n ↦ {M : Multiset β„• | M.sum = (n)! ∧ βˆ€ m ∈ M, βˆƒ k ∈ Icc 1 n, m = (k)!}.ncard) : (βˆƒ C : ℝ, βˆ€ n : β„•, n β‰₯ 2 β†’ n ^ (n ^ 2 / 2 - C * n) * Real.exp (-(n ^ 2) / 4) ≀ f n ∧ f n ≀ n ^ (n ^ 2 / 2 + C * n) * Real.exp (-(n ^ 2) / 4)) := sorry
00f67e7f6e141a6d
putnam_1992_b6
theorem putnam_1992_b6 (n : β„•) (npos : 0 < n) (M : Set (Matrix (Fin n) (Fin n) ℝ)) (h1 : 1 ∈ M) (h2 : βˆ€ A ∈ M, βˆ€ B ∈ M, Xor' (A * B ∈ M) (-A * B ∈ M)) (h3 : βˆ€ A ∈ M, βˆ€ B ∈ M, (A * B = B * A) ∨ (A * B = -B * A)) (h4 : βˆ€ A ∈ M, A β‰  1 β†’ βˆƒ B ∈ M, A * B = -B * A) : M.encard ≀ n ^ 2 := sorry
ce8b3f8c757d0267
putnam_2008_a5
theorem putnam_2008_a5 (n : β„•) (nge3 : n β‰₯ 3) (f g : Polynomial ℝ) (hfg : βˆƒ O z : β„‚, z β‰  0 ∧ βˆ€ k : β„•, k ∈ Icc 1 n β†’ (f.eval (k : ℝ)) + Complex.I * (g.eval (k : ℝ)) = O + z * Complex.exp (Complex.I * 2 * Real.pi * k / n)) : (f.natDegree β‰₯ n - 1 ∨ g.natDegree β‰₯ n - 1) := sorry
3bc162013071576b
putnam_2018_a5
theorem putnam_2018_a5 (f : ℝ β†’ ℝ) (h0 : f 0 = 0) (h1 : f 1 = 1) (hpos : βˆ€ x : ℝ, f x β‰₯ 0) (hf : ContDiff ℝ ⊀ f) : βˆƒ n > 0, βˆƒ x : ℝ, iteratedDeriv n f x < 0 := sorry
b331b74977de4c0c
putnam_1985_b2
abbrev putnam_1985_b2_solution : β„• β†’ β„• := sorry -- fun n ↦ ite (n = 101) 99 0 /-- Define polynomials $f_n(x)$ for $n \geq 0$ by $f_0(x)=1$, $f_n(0)=0$ for $n \geq 1$, and \[ \frac{d}{dx} f_{n+1}(x) = (n+1)f_n(x+1) \] for $n \geq 0$. Find, with proof, the explicit factorization of $f_{100}(1)$ into powers of distinct pr...
0722e9e37484a412
putnam_1968_a4
theorem putnam_1968_a4 (n : β„•) (S : Fin n β†’ (EuclideanSpace ℝ (Fin 3))) (hS : βˆ€ i : Fin n, dist 0 (S i) = 1) : βˆ‘ i : Fin n, βˆ‘ j : Fin n, (if i < j then (dist (S i) (S j))^2 else (0 : ℝ)) ≀ n^2 := sorry
97ddc75f447c1012