conférencier: Prof. L.H. Kauffman (Chicago)
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titre: Classifying rational tangles and rational knots
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resume:
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A tangle is a weaving pattern obtained from two parallel strands 
embedded in three dimensional space via successive twisting of the ends 
of adjacent strands. Two tangles are equivalent if one can be topologically 
deformed into the other without moving the ends and with the isotopy restricted
to a ball from which emanate the strand ends. A rational knot or link is 
obtained by identifying the ends of the strands of a rational tangle in pairs. 
This talk will give an elementary new proof of the classification of rational 
tangles and rational knots due to the speaker and Sofia Lambropoulou. We shall 
discuss problems related to generalizing these results, relations with coloring
link diagrams and applications to DNA recombination.