Site Map. This page is located on the web at http://pok.acm.org.This page was last updated Mar 11, 2015. Go to Google Development Group (GDG) Hudson Valley at www.meetup.com/gdg-hudson-valley/ to find an amazing selection of technical and entrepreneurial organizations. Poughkeepsie Chapter of the Association For Computing Machinery aaa ccccccc mmmmm mmmmm a a cc cc mm mm mm mm aa aa cc c mm mm mm mm aaaaaaaaa cc mm mmm mm aa aa cc c mm m mm MEETING NOTICE aa aa cc cc mm mm aa aa cccccccc mm mm Program: Minimal Angular Determinations for Convex Polygons Speaker: Dr. Donald Silberger, donaldsilberger@gmail.com About the Program: At each of the n vertices of a convex n-gon there are exactly (n-1)(n-2) angles. So the set A(n) of all "vertex-jointed" angles of such an n-gon is of size n(n-1)(n-2)/2. By an "angular determination" for the set U(n) of all convex n-gons we mean any subset B of A(n) such that every two convex n- gons whose angle sizes agree throughout B will agree throughout A(n); i.e., the two n-gons will be similar in the usual Euclidean sense. We study the mads for U(n) and for interesting subsets of U(n), where the word "mad" is acronymic for "minimal angular determination". Main Theorem: Every mad for U(n) contains exactly 2n-4 angles. In 2010, a paper by Disser, Mihalak, and Widmeyer showed that knowing the sizes of all n(n-1)(n-2)/2 angles of a plane (not necessarily convex) n-gon enables the construction of a similar n-gon. Their paper alludes to others apparently authored by roboticists and other computer scientists. About the Speaker: Donald Silberger is an Emeritus in the SUNY-NewPaltz Mathematics Department, and a retired Head of its Graduate Program. He received his AB in physics from Harvard, and his MS and PhD in mathematics from the University of Washington. He has taught a total of two years in high school and fifty years in colleges and universities in the Americas. He has directed 14 Masters theses, several of which resulted in papers that appeared in the research literature. He has published with a large number of his colleagues and students. Thus far, three dozen of his articles occur in refereed journals, and -- at age 85 -- he is still producing new results. All of his work deals with down-to- earth questions, which can be understood by a serious listener with little advanced mathematical background; he seeks live collaborators of all ages. His main mathematical interests include algebra, logic, number theory, combinatorics, topology, graph theory, and elementary Euclidean geometry. When: 7:30 pm, Monday, March 16, 2015 Where: Presentation Room (2d floor, Rm 2023) Hancock Center, Marist College Directions: Building 15 on the map at www.marist.edu/welcome/map.html Parking: You can park at black dot Number 27 on the map at www.marist.edu/welcome/map.html or in the lot east of Route 9, southeast of the former Main Entrance. Cost: Free and open to the public Dinner: 6 pm, Palace Diner, 845.473.1576 Map and menu: www.thepalacediner.com All are welcome to join us for dinner. We thank Marist College for hosting the chapter's meetings. Refreshments are served after the meeting. For further information, email collier@acm.org or call 845.522.1971. P - L - E - A - S - E P - O - S - T