public boolean overlapSave(SphereCluster other){
  double minDist=Math.sqrt(2) * (getRadius() + other.getRadius());
  double diff=getCenterDistance(other) - minDist;
  return diff > 0;
}

public boolean overlapSave ( SphereCluster other ) { double minDist = Math . sqrt ( 2 ) * ( getRadius ( ) + other . getRadius ( ) ) ; double diff = getCenterDistance ( other ) - minDist ; return diff > 0 ; }
when a clusters looses points the new minimal bounding sphere can be partly outside of the originating cluster . if a another cluster is right next to the original cluster ( without overlapping ) , the new cluster can be overlapping with this second cluster . overlapsave will tell you if the current cluster can degenerate so much that it overlaps with cluster ' other '
