**
For a calendar of technical society meetings in the Mid-Hudson Valley go to:
****
****http://pok.acm.org/calendar.html****
****
and/or to MHVLUG's calendar at
**http://hvstem.org/

**
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
**

**Program:**
** **
**Minimal Angular Determinations for Convex Polygons**

**When:**
** **
**7:30 pm, Monday, March 16**
^{
th
}
**, 2015**

**Where:**
** **
**Presentation Room (2**
^{
nd
}
** floor, Rm 2023)**

**
Hancock Center, Marist College
**
** ****
**

**Directions:****
Building #16 on the map at
****
****http://www.marist.edu/welcome/map.html**

**Parking:**** ****Please
park at black dot #11 on ****http://www.marist.edu/welcome/map.html****
****
(the lot North of the Hancock Center #16) or in
the lot East of Route 9, S/E of the former Main Entrance.
**

**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, "minimal angular determination", for U(n) and for interesting subsets of U(n).
**

**
Main Theorem: Every mad for U(n) contains exactly 2n-4 angles.
**

**
In 2010, a paper by Disser, Mihalak, and Widmeyer shows 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:****
****
**
**
Dr. Silberger is an Emeritus in the SUNY-NewPaltz Mathematics Dept., & a retired Head of its Graduate Program. He received his AB in physics from Harvard, and his MS & PhD in mathematics from the University of Washington. He's taught 2 years in high school and 50 years in colleges & universities in the Americas. He's directed 14 Masters theses, several of which resulted in papers that appeared in the research literature. He's published with a large number of his colleagues & students. So far, 3 dozen of his articles occur in refereed journals, and, at age 85, he is still producing new results. All 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.
**

**Cost: Our****
meeting is ****Free****
and open to the public**

**Dinner: ****6:00
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
**

This page is available on the web at http://pok.acm.org.