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a. The puppy problem b. Special cases: blind vs. stubborn, puppies vs. guppies c. Configurations and the puppy diagram (Look, actual code!) d. Counting essential critical cycles e. Rubber bands on a…
Date of creation
12/8/2020 12:00 AM
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a. Shortest non-separating cycles b. Menger's theorem c. Planarizing with at most g cycles via cycles: O(sqrt{gn} log g) d. Greedy tree-cotree again again e. Planarixing via level slicing and…
Date of creation
12/3/2020 12:00 AM
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a. Carvings b. Branch decompositions c. Dynamic programming c. Radial and medial maps d. Radial greedy tree-cotree decomposition e. Branchwidth ≤ diameter ≠ 1 f. Low-diameter slicing
Date of creation
12/1/2020 12:00 AM
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a. 1-chains = pseudoflows, circulations b. 2-chains = face potentials = Alexander numberings, boundary circulations c. Real-homology d. cycles, cocycles, and homology annotations e. Duality between…
Date of creation
11/19/2020 12:00 AM
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a. Even subgraphs, cycle space, edge cuts, and cut spaceb. Planar duality c. Boundary subgraphs d. Z2-homology e. Systems of cycles and cocycles f. Homology anotations g. Dual of minimum cut is…
Date of creation
11/17/2020 12:00 AM
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a. Planarization b. Contractible versus separating c. Thomassen's 3-path condition ⇒ O(n³) time d. Greedy tree-cotree decompositions e. Greedy (reduced) cut graph ⇒ O(n² log…
Date of creation
11/12/2020 12:00 AM
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a. Modeling curves on surfaces as walks in maps b. Spur and face moves c. System of loops d. Contractible in surface = closed in universal cover e. Dehn's lemma f. Dehn's algorithm g.…
Date of creation
11/10/2020 12:00 AM
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a. Kerékjártó-Rado theorem (Every surface supports a map.) b. Tree-cotree decompositions and systems of loops c. Detaching handles by contracting two-sided loops d.…
Date of creation
10/29/2020 12:00 AM
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a. 2-manifolds b. Polygonal schemata c. Cellular embeddings and rotation systems d. Orientation and genus e. Band decompositions f. Reflection systems g. Deletion and contraction in reflection systems
Date of creation
10/27/2020 12:00 AM
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a. FR-Dijkstra summary b. O(n log log n) minimum cut overview c. Technical details d. Planar maximum flow history e. Venkatesan's duality between flows and shortest paths f. Parametric shortest…
Date of creation
10/23/2020 12:00 AM
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a. Monge heap operations: Revealing columns and hiding rows b. Range minimum queries c. Monge heap implementation d. High-level overview of FR-Dijkstra e. Monge structure of nice r-divisions f.…
Date of creation
10/20/2020 12:00 AM
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a. Duality: Shortest essential cycle b. Crosses shortest path at most once c. Slicing into a shortest-path problem d. Easy algorithms: Brute force and MSSP e. Divide-and-conquer: O(n log k) time f.…
Date of creation
10/15/2020 12:00 AM
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a. Dense distance graphs b. Improving Dijkstra to O(n log log n) time c. Repricing d. Nested dissection e. Monge arrays and SMAWK f. Planar distances are (almost) Monge) g. Shortest paths with…
Date of creation
10/13/2020 12:00 AM
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a. Tree separators b. Fundamental cycle separators c. BFS level separators d. Face-level cycles e. Short cycle separators f. Good r-divisions
Date of creation
10/9/2020 12:00 AM
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a. Problem statement b. Shortest paths and slacks c. Disk-tree lemma and compact output d. Red and blue vertices, active darts e. Dynamic forest data structures f. Summary: O(n) pivots, each in O(log…
Date of creation
10/6/2020 12:00 AM
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a. Tutte drawings b. Physical intuition: energy minimization c. Halfplane lemma d. No degenerate vertex neighborhoods e. No degenerate faces
Date of creation
10/1/2020 12:00 AM
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a. Simple triangulation lemma b. Hole filling (Every pentagon is star-shaped) c. Vertex deletion d. Schnyder woods e. Grid embedding
Date of creation
9/29/2020 12:00 AM
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a. Deletion and contraction in abstract graphs b. Spanning trees c. Planar duality: (Σ\e)* = Σ*/e* d. Implementing deletion and contraction in maps e. Cycle-cut duality f. Tree-cotree…
Date of creation
9/24/2020 12:00 AM
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a. What is a graph? (vertices and darts) b. Incidence list and incidence array data structures c. Planar maps: faces, shores, face degree d. Rotation systems e. Stereographic projection f. Planar map…
Date of creation
9/22/2020 12:00 AM
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a. Steinitz's contraction algorithm (spindle removal) b. Rotation number: Smiles minus frowns c. Rotation number: Initial winding and writhe d. Defect
Date of creation
9/18/2020 12:00 AM
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a. Winding numbers and Alexander numbering b. Gauss smoothing and Seifert decompositions c. Gauss' parity condition and the Nagy graph d. Dehn smoothing and Euler tours e. Tree-onion…
Date of creation
9/15/2020 12:00 AM
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a. Definitions: transverse intersection, generic curve (immersion) b. Isotopy c. Image graphs and their faces d. Homotopy moves e. Planarity: F = V+2 f. Gauss codes and Gauss diagrams g. Tracing…
Date of creation
9/10/2020 12:00 AM
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a. Shortest paths in simple polygons b. Crossing sequences via triangulation c. Dual tree of a polygon triangulation d. The funnel algorithm e. Adding holes: Nothing changes! f. Universal cover:…
Date of creation
9/8/2020 12:00 AM
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a. Quadratic lower bound? b. Trapezoidal decomposition c. Bentley-Ottmann sweep-line algorithm d. Horizontal and vertical ranks e. Rectification f. Sliding brackets g. Overall time analysis
Date of creation
9/3/2020 12:00 AM
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