Study of invariants and geometric structures by local moves in Knot Theory

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A circle in the 3-dimensional space is called a knot. There exist many kinds of knot since the difference of the dimensions between a knot and a space where a knot exists is two. When we project a knot into the plane and give the over and under crossing information, we have the figure called a knot diagram. A knot whose any diagram has not only real crossings but also virtual crossings is called a virtual knot.A local move is the operation which changes the local figure into another figure on a knot diagram. If two knots or two virtual knots can be transformed into each other by local moves, the minimal number of necessary local moves can be considered as a metric. We study relations between the positions of knots in the metric space of knots by a local move and knot invariants, and the property of this metric space, for example, the width of the metric space.