
 PlanetMath: hyperbolic fixed point (Site not responding. Last check: 20071007) 
  If the dimension of the stable manifold of a fixed point is zero, the point is called a source; if the dimension of its unstable manifold is zero, it is called a sink; and if both the stable and unstable manifold have nonzero dimension, it is called a saddle. 
  Crossreferences: stable, point, stable manifold, dimension, iterate, least period, periodic point, linear hyperbolic isomorphism, diffeomorphism, fixed point, smooth manifold 
  This is version 3 of hyperbolic fixed point, born on 20030727, modified 20030729. 
 planetmath.org /encyclopedia/HyperbolicFixedPoint.html (149 words) 
