helaman ferguson sculpture: Seven Decades, triply punctured torus from a 7th root of unity with negative curvature

Provenance:

Ken Hoffman's 70th birthday present from his family, they all contributed to the piece, Professor Kathleen Hoffman and her husband Bob (Ken's son) facilitated this project.

Collection of:

Kenneth and Gabriella Hoffman, Eastern Shore, Maryland

Exhibition:

National Science Foundation, Arlington, Virginia

Dimensions:

14" x 14" x 12"

Material:

Carnelian red dakota granite

Engraved material:

Z + Ze^{2 π √-1 / 7} → C ⇒ C/(Z + Ze^{2 π}√-1 / 7) ≈ S¹ × S¹

Weight:

35 lbs

Seven Decades corresponds to an complex elliptic curve defined by the two dimensional complex plane lattice defined by the two linearly independent generators of unity and a primitive seventh root of unity. As a triply punctured torus with negative curvature, this piece directly carved in granite has the feature that every point is the keystone of a saddle web of arches. Very strong.

Helaman Ferguson, Bilbao Congress paper, Contemporary Mathematics, Volume 288, 2001, pages 39-57. There is a full page picture of this piece on page 40.

Photo credit is Sunforge Studios