Yoshiyuki OHYAMA

Department of Mathematics, Tokyo Woman's Christian University

Japanese page

Mathematics of Knots III

Research Interests: Knot Theory

１．Local moves on a knot diagram
２．Vassiliev invariants of knots
３．Virtual knots
4．Vassiliev type invariants for spatial graphs

Papers (2010-)

S.Horiuchi and Y.Ohyama: Almost alternating knots producing an alternating knot,
J. Knot Theory Ramifications, Vol.19, No.4 (2010), 503-507. pdf

S.Horiuchi and Y.Ohyma: A numerical invariant for two component spatial graphs,
J. Knot Theory Ramifications, Vol.19, No.9 (2010), 1125-1134. pdf

S.Horiuchi and Y.Ohyama: On the Cn-distance and Vassiliev invariants,
J. Knot Theory Ramifications, Vol.21, No.10 (2012), 1250097 (22 pages).
DOI: 10.1142/S02182165125009761250097. pdf

S.Horiuchi, K.Komura Y.Ohyama and M.Shimozawa: The Gordian complex of virtual knots,
J. of Knot Theory Ramifications, Vol. 21, No.14(2012), 1250122 (11 pages)
DOI: 10.1142/S0218216512501222,

S.Horiuchi and Y.Ohyama: A two dimensional lattice of knots by C2n-moves,
Mathematical Proceedings of the Cambridge Philosophical Society, Vol.155(1), (2013), 39-46.
DOI:10.1017/S0305004113000017

S.Horiuchi Y.Ohyama: The Gordian complex of virtual knots by forbidden moves,
J. of Knot Theory Ramifications, Vol. 22, No.9(2013), 1350051 (11 pages)
DOI: 10.1142/S021821651350051X

S.Horiuchi and Y.Ohyama: Intersection of two spheres in the metric space of knots by Cn-moves,
J. Knot Theory and Ramifications Vol. 23, No. 4 (2014) 1450019 (10 pages).
DOI: 10.1142/S0218216514500199

S.Horiuchi and Y.Ohyama: Geodesic graphs for a homotopy class of virtual knots,
J. Knot Theory and Ramifications Vol. 26, No. 13 (2017) 1750090 (10 pages).
DOI: 10.1142/S0218216517500900

Y.Ohyama and M.Sakurai: Virtualization and n-writhes for virtual knots,
J. Knot Theory and Ramifications Vol. 28, No. 12 (2019) 1950074 (9 pages).
DOI: 10.1142/S0218216519500743

Y.Ohyama and M.Sakurai: A virtual knot with the virtual unknotting number one
and a sequence of n-writhes, submitted.

Y.Ohyama and M.Sakurai: Virtual knots with properties of Kishino's knot, preprint.