March - May 2014



MARCH 27:   Ralph Kopperman, CCNY, will discuss "Two fixed point theorems". At CCNY; tea 3:30 pm, NAC 8/130, talk 4 pm, NAC 6/306. For more information, contact Ralph Kopperman,

     ABSTRACT:   The classical contraction fixed point theorem is shown to extend to weighted quasimetric spaces which allow negative weight. The result then may be a criterion to decide whether certain algorithms will simultaneously add correct information and remove contradictory information.

      We also discuss a topological setting that naturally exists precisely around fixed points of self-maps.


APRIL 11:   Lucas Oliviera, CUNY PhD Program in Computer Science, will discuss "Using a Topological Descriptor to Investigate Structures of Virus Particles." At CUNY Graduate Center, Fifth Avenue and 34th Street, New York, NY 10016, Room 4421. Tea 3:30-4 p.m., talk 4-5 p.m., discussion 5-5:30 p.m. Co-presented by the Digital Imaging and Graphics Group, CUNY PhD program in Computer Science. For more information, contact R. Kopperman, or Gabor Herman,

     ABSTRACT:   An understanding of the 3-dimensional structure of a biological macromolecular complex is essential to fully understand its function. A component tree is a topological and geometric image descriptor that captures information regarding the structure of an image based on the connected components determined by different grayness thresholds. We believe interactive visual exploration of component trees of (the density maps of) macromolecular complexes can yield much information about their structure. To illustrate how component trees can convey important structural information, we consider component trees of four recombinant mutants of the procapsid of a bacteriophage (cystovirus phi6), and show how differences between the component trees reflect the fact that each non-wild-type mutant of the procapsid has an incomplete set of constituent proteins.


For more information, contact:

CCNY (212-650-5346): R. Kopperman, S. Popvassilev
College of Staten Island (718-982-3626): P. R. Misra
Baruch College (646-312-4136): A. Todd
LIU C. W. Post Center (516-299-2447): S. Andima
Medgar Evers College, (718-270-6416): H. Pajoohesh
Queensborough Community College, (718-281-5291): F. Jordan