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Source labels openGreen's Open Problems · Combinatorics

Ben Green's Open Problem 19: Upper

[Ma21] showed that C4C \leq 4.

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openErdős Problems · Number theory

Erdős Problem 357: I

Let h(n)h(n) be the maximal kk such that there exist integers 1a1akn1 \le a_1 \leq \dotsc \leq a_k \le n such that all sums of the shape uivai\sum_{u \le i \le v} a_i are distinct. Is h(n)=o(n)h(n)=o(n)?

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openGreen's Open Problems · Combinatorics

Green's Open Problem 22

If {1,,N}\{1, \ldots, N\} is rr-coloured then, for NN0(r)N \geqslant N_0(r), there are integers x,y3x, y \geqslant 3 such that x+y,xyx + y, xy have the same colour.

Find reasonable bounds for N0(r)N_0(r). The goal is to improve upon the Green-Sawhney bound.

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openErdős Problems · Number theory

Erdős Problem 357: Big O Version

Let h(n)h(n) be the maximal kk such that there exist integers 1a1akn1 \le a_1 \leq \dotsc \leq a_k \le n such that all sums of the shape uivai\sum_{u \le i \le v} a_i are distinct. How does h(n)h(n) grow? Can we find a (good) explicit function gg such that g=O(h)g = O(h) ?

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openGreen's Open Problems · Combinatorics

Green's Open Problem 24

If AA is a set of nn integers, what is the maximum number of affine translates of the set {0,1,3}\lbrace 0,1,3 \rbrace that AA can contain?

Conjectured in [Aa19] p.579: (13+o(1))n2\left({1}{3} + o(1)\right) n^2.

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openErdős Problems · Number theory

Erdős Problem 357: Big O Version Symm

Let h(n)h(n) be the maximal kk such that there exist integers 1a1akn1 \le a_1 \leq \dotsc \leq a_k \le n such that all sums of the shape uivai\sum_{u \le i \le v} a_i are distinct. How does h(n)h(n) grow? Can we find a (good) explicit function gg such that h=O(g)h = O(g) ?

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openGreen's Open Problems · Combinatorics

Green's Open Problem 24

Conjecture p.579 in [Aa19]: (13+o(1))n2\left({1}{3} + o(1)\right) n^2.

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openErdős Problems · Number theory

Erdős Problem 357: Big Theta Version

Let h(n)h(n) be the maximal kk such that there exist integers 1a1akn1 \le a_1 \leq \dotsc \leq a_k \le n such that all sums of the shape uivai\sum_{u \le i \le v} a_i are distinct. How does h(n)h(n) grow? Can we find a (good) explicit function gg such that h=Θ(g)h = \Theta(g) ?

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openGreen's Open Problems · Combinatorics

Green's Open Problem 25

For which values of kk is the following true: whenever we partition [N]=A1Ak[N] = A_1 \cup \dots \cup A_k, i=1k(Ai+^Ai)110N\left|\bigcup^k_{i=1} (A_i \hat{+} A_i)\right| \geq \frac{1}{10} N?

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openErdős Problems · Number theory

Erdős Problem 357: Little O Version

Let h(n)h(n) be the maximal kk such that there exist integers 1a1akn1 \le a_1 \leq \dotsc \leq a_k \le n such that all sums of the shape uivai\sum_{u \le i \le v} a_i are distinct. How does h(n)h(n) grow? Can we find a (good) explicit function gg such that g=o(h)g = o(h) ?

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openGreen's Open Problems · Combinatorics

Green's Open Problem 25: Upper

We conjecture that the best-known upper bound can be lowered.

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openErdős Problems · Number theory

Erdős Problem 357: Little O Version Symm

Let h(n)h(n) be the maximal kk such that there exist integers 1a1akn1 \le a_1 \leq \dotsc \leq a_k \le n such that all sums of the shape uivai\sum_{u \le i \le v} a_i are distinct. How does h(n)h(n) grow? Can we find a (good) explicit function gg such that h=o(g)h = o(g) ?

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openGreen's Open Problems · Combinatorics

Green's Open Problem 25: Lower

We conjecture that the best-known lower bound can be raised.

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openErdős Problems · Number theory

Erdős Problem 359: I

Let a1<a2<a_1< a_2 < ⋯ be an infinite sequence of integers such that a1=1a_1=1 and ai+1a_{i+1} is the least integer which is not a sum of consecutive earlier aja_js. Show that ak/ka_k / k \to \infty.

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openGreen's Open Problems · Combinatorics

Green's Open Problem 26

The analogous problem in Fpn\mathbb{F}^n_p remains open. [Gr24]

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openErdős Problems · Number theory

Erdős Problem 359: Ii

Let a1<a2<a_1< a_2 < ⋯ be an infinite sequence of integers such that a1=1a_1=1 and ai+1a_{i+1} is the least integer which is not a sum of consecutive earlier aja_js. Show that ak/k1+c0a_k / k ^ {1 + c} \to 0 for any c>0c > 0.

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openGreen's Open Problems · Combinatorics

Green's Open Problem 27: Equivalent

What is the size of the smallest set AZ/pZA \subset \mathbb{Z} / p\mathbb{Z} (with at least two elements) for which no element in the sumset A+AA + A has a unique representation?

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openErdős Problems · Number theory

Erdős Problem 359: Is Good For 1 Asymptotic

Suppose monotone sequence AA satisfies the following: A 0 = 1 and for all j, A (j + 1) is the smallest natural number that cannot be written as a sum of consecutive terms of A 0, ..., A j. Then it is conjectured that ak klogkloglogka_k ~ \frac{k \log k}{\log \log k}.

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openGreen's Open Problems · Combinatorics

Green's Open Problem 27: Lower

Propose a better lower bound along primes.

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openErdős Problems · Number theory

Erdős Problem 361: Big O

Let c>0c > 0 and nn be some large integer. What is the size of the largest set A{1,,cn}A \subseteq \{1, \ldots, \lfloor c n \rfloor\} such that nn is not a sum of a subset of AA? Does this depend on nn in an irregular way?

Source checked Jul 26, 20261 pinned Lean statementInspect problem