by Terrence Bisson | Jul 20, 2018 | Uncategorized

I will be posting something about Heron’s formula for the area of a triangle, and Tartaglia’s formula for the volume of a tetrahedron.
by Terrence Bisson | Jul 5, 2018 | Uncategorized

In the first draft of this post, from July 5, I suggested a project to study configurations in space of a ring made of four sticks of known lengths. But in talking with McSteve we realized that the project was really best thought of in terms tetrahedra, so I am...
by Terrence Bisson | Jun 14, 2018 | Uncategorized

Project 1: The tetrahelix turns out to be a sequence of points H(n)= (r cos(theta n),r sin(theta n), m n) on a helix, where the constants r, theta, m should be determined by the requirement that each edge of the tetrahedron H(n) H(n+1) H(n+2) H(n+3) has length 1. ...
by Terrence Bisson | Jun 8, 2018 | Uncategorized

K. Walker, Configuration spaces of linkages, undergrad.thesis, princeton 1965 http://canyon23.net/math/ Kevin Walker’s post of thesis says error in proof of 3.3, see Hausmann, sur la topologie des bras articules ’89 (I have a photocopy) +++...
by Terrence Bisson | May 31, 2018 | Uncategorized

Some references to gluing together tetrahedra. J. H. Mason, Can regular tetrahedra be glued together face to face to form a ring? Math. Gaz., 56 (1972), 194-197. S. K. Stein, The Planes Obtainable by Gluing Regular Tetrahedra. The American Mathematical Monthly, Vol....