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12 votes
0 answers
240 views

Does $2^{\aleph_0}\rightarrow [\aleph_1]^2_3$ require that the continuum is weakly inaccessible?

A classic result of Sierpiński shows that $2^{\aleph_0}\nrightarrow [\aleph_1]^2_2$, that is, there is a coloring of pairs of real numbers using two colors such that both colors appear on any ...
Todd Eisworth's user avatar
8 votes
1 answer
360 views

A combinatorial property of uncountable groups, II

Problem 1. Is it true that each uncountable group $G$ contains two subsets $A,B\subset G$ such that 1) for any $x,y\in G$ the intersection $xA\cap yB$ is finite and 2) for any function $\...
Taras Banakh's user avatar
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3 votes
2 answers
672 views

Partition calculus question

For $m,n,k < \omega$, consider the equation $X \to (\omega \times k)^{m}_{n}$ What is the smallest $X$ known to satisfy it? Baumgartner-Hajnal theorem gives a satisfactory answer for $m=2$, but ...
Artem Chernikov's user avatar
1 vote
0 answers
99 views

Group graphs and Ramsey theory. Sub-question 1

Question: Find/compute relations between the classical Ramsey numbers and their variations (described below) -- exact or asymptotic. A graph is a set $\ X\ $ together with a (coloring) function $\ c:\...
Wlod AA's user avatar
  • 4,776