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Correction to the paper: "A theorem on almost disjoint sets'' (Colloq. Math. 24 (1972), 1--2)

B. Rotman (1975)

Colloquium Mathematicae

Countable partitions of the sets of points and lines

James Schmerl (1999)

Fundamenta Mathematicae

The following theorem is proved, answering a question raised by Davies in 1963. If $L_{0} \cup L_{1} \cup L_{2} \cup . . .$ is a partition of the set of lines of $ℝ^{n}$ , then there is a partition $ℝ^{n} = S_{0} \cup S_{1} \cup S_{2} \cup . . .$ such that $| ℓ \cap S_{i} | \leq 2$ whenever $ℓ \in L_{i}$ . There are generalizations to some other, higher-dimensional subspaces, improving recent results of Erdős, Jackson Mauldin.

Counterexamples in minimally generated Boolean algebras

Sabine Koppelberg (1988)

Acta Universitatis Carolinae. Mathematica et Physica

Covering the plane with sprays

James H. Schmerl (2010)

Fundamenta Mathematicae

For any three noncollinear points c₀,c₁,c₂ ∈ ℝ², there are sprays S₀,S₁,S₂ centered at c₀,c₁,c₂ that cover ℝ². This improves the result of de la Vega in which c₀,c₁,c₂ were required to be the vertices of an equilateral triangle.

Cylinder problem

K. Ciesielski, F. Galvin (1987)

Fundamenta Mathematicae

Displaying 21 – 25 of 25

Correction to the paper: "A theorem on almost disjoint sets'' (Colloq. Math. 24 (1972), 1--2)

Countable partitions of the sets of points and lines

Counterexamples in minimally generated Boolean algebras

Covering the plane with sprays

Cylinder problem

Currently displaying 21 – 25 of 25