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Open-problem statements, with their sources attached.

Each statement record keeps the mathematical question, a dated status source, accessible references, and any pinned Lean formulation separate from proof verification.

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Source labels openGreen's Open Problems · Combinatorics

Green's Open Problem 52

Suppose that AF2nA \subset \mathbb{F}_2^n is a set with an additive complement of size KK. Does 2A2A contain a coset of codimension OK(1)O_K(1)?

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

Green's Open Problem 52

Could 2A2A even contain a coset of codimension O(logK)O(\log K)?

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

Ben Green's Open Problem 58

Suppose A,B{1,,N}A, B ⊆ \{1, \dots, N\} both have size at least N0.49N^{0.49}. Must the sumset A+BA + B contain a composite number?

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

Ben Green's Open Problem 72

The no-k-in-line problem: For NkN \geq k and k>2k > 2, the AllowedSetSize is (k1)N(k - 1) N, i. e. on an N×NN \times N subset, there is a set of (k1)N(k - 1) N points for which no kk lie on a line (and not such a set of bigger size).

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

Ben Green's Open Problem 72

Green's Open Problem 72 / No-three-in-line problem*: The no-k-in-line conjecture holds for k=3k = 3.

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

Ben Green's Open Problem 72: Eventually

Does the no-three-in-line problem hold when NN is big enough?

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

Ben Green's Open Problem 77

Given nn points in the unit disc, must there be a triangle of area at most n2+o(1)n^{-2+o(1)} determined by them?

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

Green's Open Problem 9

Problem 9 (ii): is r5(N)N(logN)cr_5(N) \ll N(\log N)^{-c}?

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

Green's Open Problem 9

Problem 9 (iii): is r4(F5n)N1cr_4(\mathbf{F}_5^n) \ll N^{1-c}, where N=5nN=5^n?

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openOpen Quantum Problems · Combinatorics

Open Quantum Problem 13: Mutually unbiased bases

Special case in dimension 66: determine the maximal number of mutually unbiased orthonormal bases in C6\mathbb{C}^6.

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openOpen Quantum Problems · Combinatorics

Open Quantum Problem 13: Mutually unbiased bases

Special case in dimension 1010 (not a prime power): determine the maximal number of mutually unbiased orthonormal bases in C10\mathbb{C}^{10}.

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openOpen Quantum Problems · Combinatorics

Open Quantum Problem 13: Mutually unbiased bases

Special case in dimension 1212 (not a prime power): determine the maximal number of mutually unbiased orthonormal bases in C12\mathbb{C}^{12}.

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openOpen Quantum Problems · Combinatorics

Open Quantum Problem 13: Mutually unbiased bases

Special case in dimension 1414 (not a prime power): determine the maximal number of mutually unbiased orthonormal bases in C14\mathbb{C}^{14}.

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openOpen Quantum Problems · Combinatorics

Open Quantum Problem 13: Mutually unbiased bases

Special case in dimension 1515 (not a prime power): determine the maximal number of mutually unbiased orthonormal bases in C15\mathbb{C}^{15}.

Source checked Jul 26, 20261 pinned Lean statementInspect problem
Source labels openOpen Quantum Problems · Combinatorics

Open Quantum Problem 13: Mutually unbiased bases

Open Quantum Problem 13: determine the maximal number of mutually unbiased orthonormal bases in Cd\mathbb{C}^d for d2d \ge 2.

Source checked Jul 26, 20261 pinned Lean statementInspect problem