18.319 | Fall 2005 | Graduate

Geometric Combinatorics

Readings

LEC # TOPICS READINGS
1 Sylvester-Gallai Theorem, Scott’s Problem about the Number of Distinct Slopes in the Plane Aigner, M., and G. M. Ziegler, eds. Proofs from the BOOK. 3rd ed. Berlin, Germany: Springer-Verlag, 2004, chapter 10, pp. 59-64. ISBN: 3540404600.
2 Scott’s Problem about the Number of Distinct Directions in Three-space Pach, János, Rom Pinchasi, and Micha Sharir. “On the Number of Directions Determined by a Three-Dimensional Points Set.” Journal of Combinatorial Theory, Series A 108, no. 1 (October 2004): 1-16.
3 Motzkin-Rabin Theorem on Monochromatic Lines Aigner, M., and G. M. Ziegler. Proofs from the BOOK. 3rd ed. Berlin, Germany: Springer-Verlag, 2004, chapter 11, pp. 59-64. ISBN: 3540404600.
4 Szemerédi-Trotter Theorem (Two Equivalent Formulations), Crossing Lemma

Szemerédi-Trotter Theorem (Two Equivalent Formulations) 
Brass, Peter, William Moser, and János Pach. Research Problems in Discrete Geometry. Berlin, Germany: Springer-Verlag, 2005, section 1.2.2. ISBN: 0387238158.

Crossing Lemma

Székely, László A. “Crossing numbers and hard Erdos problems in discrete geometry.” Combinatorics, Probability and Computing 6, no. 3 (1997): 353-358.

5 Unit Distances, Unit Area Triangles, Beck’s Two Extremities Theorem, Weak Dirac Conjecture

Unit Distances, Unit Area Triangles

Brass, Peter, William Moser, and János Pach. Research Problems in Discrete Geometry. Berlin, Germany: Springer-Verlag, 2005, sections 5.1 and 6.2. ISBN: 0387238158.

Beck’s Two Extremities Theorem, Weak Dirac Conjecture

Elekes, György. “SUMS versus PRODUCTS in number theory, algebra and Erdos geometry.” In Paul Erdos and His Mathematics, II. Edited by G. Halász, L. Lovász, M. Simonovits, and V. T. Sós. Vol 11. Bolyai Society Mathematical Studies, Berlin, Germany: Springer-Verlag, 2002, pp. 241-290. ISBN: 3540422366.

6 Crossing Lemma for Multigraphs, Minimum Number of Distinct Distances

Crossing Lemma for Multigraphs

Székely, László A. “Crossing numbers and hard Erdos problems in discrete geometry.” Combinatorics, Probability and Computing 6, no. 3 (1997): 353-358.

Minimum Number of Distinct Distances

József Solymosi and Csaba D. Tóth. “Distinct distances in the plane.” Discrete and Computational Geometry 25, no. 4 (2001): 629-634.

Brass, Peter, William Moser, and János Pach. Research Problems in Discrete Geometry. Berlin, Germany: Springer-Verlag, 2005, section 5.3. ISBN: 0387238158.

7 Pach-Sharir Theorem on Incidences of Points and Combinatorial Curves Pach, János, and Micha Sharir. “On the Number of Incidences Between Points and Curves.” Combinatorics, Probability and Computing 7, no. 1 (1988): 121-127.
8 Various Crossing Numbers, Embedding Technique

Combinatorics Seminar: New Results On Old Crossing Numbers (or Old Results On New Ones?) (PDF) (Courtesy of János Pach and Geza Toth. Used with permission.)

Various Crossing Numbers

Pach, János, and Géza Tóth. “Which crossing number is it anyway? " Journal of Combinatorial Theory Ser B 80, no. 2 (2000): 225-246.

Brass, Peter, William Moser, and János Pach. Research Problems in Discrete Geometry. Berlin, Germany: Springer-Verlag, 2005, section 9.4. ISBN: 0387238158.

Embedding Technique

Székely, László A. “Short proof for a theorem of Pach, Spencer, and Tóth.” In Towards a Theory of Geometric Graphs (Volume 342 of Contemporary Mathematics). Providence, RI: Amer. Math. Soc. 2004, pp. 281-283. ISBN: 0821834843.

Valtr, Pavel. “On the pair-crossing number.” In Combinatorial and Computational Geometry (Volume 52 of Mathematical Sciences Research Institute Publication). Cambridge, UK: Cambridge University Press, 2005, pp. 569-575. ISBN: 0521848628.

9

More on Crossing Numbers

Sum vs. Product Sets

More on Crossing Numbers
Schaefer, Marcus, and Daniel Štefankovic. “Decidability of string graphs.” Journal of Computational System Sciences 68, no. 2 (2004): 319-334. Section 3.

Michael J. Pelsmajer, Marcus Schaefer, Daniel Štefankovic. “Odd crossing number is not crossing number.” In Proceedings of the 13th International Symposium on Graph Drawing (Lecture Notes in Computer Science) Berlin, Germany: Springer-Verlag, 2005. (To appear).

Sum vs. Product Sets

Solymosi, József. “On the number of sums and products.” Bull London Math Soc 37, no. 4 (2005): 491-494.

10 Lipton-Tarjan and Gazit-Miller Separator Theorems

Lipton, Richard J., and Robert Endre Tarjan. “A separator theorem for planar graphs.” SIAM Journal on Applied Mathematics 36, no. 2 (1979): 177-189.

Gazit, Hillel, and Gary L. Miller. “Planar separators and the Euclidean norm (PDF).” In Algorithms (Volume 450 of Lecture Notes in Computer Science). Berlin, Germany: Springer-Verlag, 1990, pp. 338-347. ISBN 3540529217.

11 Cutting Circles into Pseudo-segments, Lenses, Transversal and Packing Numbers, d-intervals

Cutting Circles into Pseudo-segments

Tamaki, Hisao, and Takeshi Tokuyama. “How to cut pseudoparabolas into segments.” Discrete and Computational Geometry 19, no. 2 (1998): 265-290.

Transversal and Packing Numbers, d-intervals

Kaiser, Tomáš. “Transversals of d-intervals.” Discrete and Computational Geometry 18, no. 2 (1997): 195-203.

Alon, Noga. “Piercing d-intervals.” Discrete and Computational Geometry 19, no. 3 (1998): 333-334.

Matoušek, Jirí. “Lower bounds on the transversal numbers of d-intervals.” Discrete and Computational Geometry 26, no. 3 (2001): 283-287.

12 Intersection Reverse Sequences Marcus, Adam, and Gábor Tardos. “Intersection reverse sequences and geometric applications.” In Proceedings of the 12th International Symposium on Graph Drawing (Volume 3383 of Lecture Notes in Computer Science). Berlin, Germany: Springer-Verlag, 2004, pp. 349-359. ISBN: 3540245286.
13 Arrangements, Levels, Lower Envelopes, Davenport-Schinzel Sequences Matoušek, Jirí. Lectures on Discrete Geometry. Berlin: Springer-Verlag, 2002, sections 6.1-6.2 and 7.1. ISBN: 0387953744.
14 Davenport-Schinzel Sequences of Order 3 Matoušek, Jirí. Lectures on Discrete Geometry. Berlin: Springer-Verlag, 2002, sections 7.2-7.3. ISBN: 0387953744.
15 Complexity of the First k-levels, Clarkson-Shor Technique, Cutting Lemma

Clarkson-Shor Technique

Sharir, Micha. “The Clarkson-Shor Technique Revisited and Extended.” Combinatorics Probability and Computation 12, no. 2 (2003): 191-201.

16 Proof of Cutting Lemma, Simplicial Partitions

Combinatorics Seminar: On The Maximum Number Of Edges In K-Quasi-Planar Graphs (PDF ) (Courtesy of Eyal Ackerman. Used with permission.)

Proof of Cutting Lemma

Matoušek, Jirí. Lectures on Discrete Geometry. Berlin, Germany: Springer-Verlag, 2002, sections 4.6 and 6.5. ISBN: 0387953744.

Simplicial Partitions

Chazelle, Bernard. The Discrepancy Method. Cambridge, UK: Cambridge University Press, 2000, section 5.3. ISBN: 0521770939.

17 Spanning Trees with Low Stabbing Numbers

Chazelle, Bernard. The Discrepancy Method. Cambridge, UK: Cambridge University Press, 2000, section 5.3. ISBN: 0521770939.

Asano, Tetsuo, Mark de Berg, Otfried Cheong, Leonidas J. Guibas, Jack Snoeyink, and Hisao Tamaki. “Spanning trees crossing few barriers.” Discrete and Computational Geometry 30, no. 4 (2003): 591-606.

18 k-levels, k-sets, Halving Lines Matoušek, Jirí. Lectures on Discrete Geometry. Berlin, Germany: Springer-Verlag, 2002, chapter 11. ISBN: 0387953744.
19 VC-dimension and ε-nets Matoušek, Jirí. Lectures on Discrete Geometry. Berlin, Germany: Springer-Verlag, 2002, sections 10.2-10.3 ISBN: 0387953744.
20 Optimal ε-approximations, Links to Discrepancy Theory Chazelle, Bernard. The Discrepancy Method. Cambridge, UK: Cambridge University Press, 2000, section 4.3. ISBN: 0521770939.
21 Binary Space Partitions

de Berg, Mark, Marc van Kreveld, Mark Overmars, and Otfried Schwarzkopf. Computational Geometry: Algorithms and Applications. 2nd ed. Berlin, Germany: Springer-Verlag, 2000, section 12. ISBN: 3540656200.

Tóth, Csaba D. “Binary space partitions: recent developments.” In Combinatorial and Computational Geometry (Volume 52 of Mathematical Science Research Institute Publications). Cambridge, UK: Cambridge University Press, 2005, pages 529-556. ISBN 0521848628.

———. “A note on binary plane partitions.” Discrete and Computational Geometry 30, no. 1 (2003): 3-16.

22 Geometric Graphs and Forbidden Subgraphs

Pach, János, and Pankaj K. Agarwal. Combinatorial Geometry. New York, NY: Wiley & Sons Inc., 1995, chapter 14. ISBN: 0471588903.

Brass, Peter, William Moser, and János Pach. Research Problems in Discrete Geometry. Berlin, Germany: Springer-Verlag, 2005, section 9.5. ISBN: 0387238158.

23 Zig-zag and Alternating Paths for Disjoint Segments

Tóth, Géza, and Pavel Valtr. “Geometric graphs with few disjoint edges.” Discrete and Computational Geometry 22, no. 4 (1999): 633-642.

Hoffmann, Michael, and Csaba D. Tóth. “Alternating paths through disjoint line segments.” Information Processing Letters 87, no. 6 (2003): 287-294.

Tóth, Csaba D. “Alternating paths along orthogonal segments.” In Proc. 8th Workshop on Algorithms and Data Structures (Ottawa, ON, 2003) (Volume 2748 of Lecture Notes in Computer Science). Berlin, Germany: Springer-Verlag, 2003, pp. 389-400. ISBN: 3540405453.

24 Crossing-free Hamiltonian Cycles and Long Monochromatic Paths

Hoffmann, Michael, and Csaba D. Tóth. “Segment endpoint visibility graphs are Hamiltonian.” Computational Geometry Theory and Applications 26, no. 1 (2003): 47-68.

Károlyi, Gyula, János Pach, Géza Tóth, and Pavel Valtr. “Ramsey-type results for geometric graphs II.” Discrete and Computational Geometry 20, no. 3 (1998): 375-388.

25 Pseudo-triangulations and Art Gallery Problems

Aigner, M., and G. M. Ziegler. Proofs from the BOOK. 3rd ed. Berlin, Germany: Springer-Verlag, 2004, chapter 31, pp. 59-64. ISBN: 3540404600.

Tóth, Csaba D. “Art gallery problem with guards whose range of vision is 180º.” Computational Geometry Theory and Applications 17, no. 3-4 (2000): 121-134.

Speckmann, Bettina, and Csaba D. Tóth. “Allocating Vertex Π-Guards in Simple Polygons via Pseudo-Triangulations.” Discrete and Computational Geometry 33, no. 2 (2005): 345-364.

Further References

Goodman, E., János Pach, and E. Welzl, eds. Combinatorial and Computational Geometry. Cambridge, UK: Cambridge University Press, 2005. ISBN: 0521848628.

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