KNOT SOLVER Ð by Lars GislŽn, Dept. of Theoretical Physics, Lund, SWEDEN
larsg@thep.lu.se

   KNOT SOLVER investigates if a "knot", which you draw with the mouse
on the screen, is reducible i. e. if by keeping the ends of the knot
fixed it can be manipulated to reduce the number of places where it
crosses itself (without cutting of course) using Reidemeister moves.
   When you have opened KNOT SOLVER  you will see an empty window with
some icons in the upper left corner. Select the pen icon. Then position
the mouse somewhere immediately to the right of the left window border.
Press the mouse button and keep it pressed while you outline the knot
you want to investigate. The "rope" will be drawn with a thin black
line. 
   Don't draw too fast and don't pass the borders of the window. Keep
some clearance between the different paths of the knot to avoid the
introduction of unwanted crossings.
   Every time the rope crosses itself there will be a brief flash around
the crossing to indicate that that is has been recognized.When the knot
is finished ensure that there is an unobstructed path from the current
cursor position to the right side of the window and release the mouse
button. The program will  automatically complete the path to the right
border.
   The rope will now be redrawn by KNOT SOLVER  with a thicker pen. The
crossings will be drawn such that it will be possible to see which part
of the rope is below and which part is above. Probably the layout of the
crossings is not the one you want, by selecting the crossing change icon
and then clicking on a crossing you can change the above/below order. 
   When you are satified with the knot choose item ""Solve Knot" from
the menu "Solve". KNOT SOLVER  will try to reduce the knot and shows its
progress by writing operation symbols and numbers at the bottom of the
window.