For a convex region R and a family F of arcs, we say that R covers F or R is a
cover for F, if R contains a congruent copy of each arc in F. The Moser’s worm
problem [2] searches the region of smallest area which contains a congruent copy
of every unit arc on the plane. A popular shape of arcs is a triangle. In 1997,
Wetzel [6] gave the smallest equilateral triangular cover for the family of all
triangles of perimeter two. Moreover, he [5] also gave the smallest rectangular
cover for the family of all triangles of perimeter two. In 2000, Furedi and Wetzel
[1] gave the smallest convex cover for the family of all triangles of perimeter two.
In 2009, Zhang and Yuan [7] gave the smallest regularized parallelogram cover,
whose length of the smaller diagonal is not less than one, for the family of all
triangles of perimeter two. In 2011, Sroysang [3,4] gave the smallest regularized
trapezoid cover, whose length of the smaller diagonal is not less than one, and two
smaller angles are opposite, for the family of all triangles of perimeter two.
1546 B. Sroysang
In this paper, we search for the smallest regular hexagon which covers the
family of all triangles of perimeter two.
The diameter of a convex set X is the maximum of the distance between the
two parallel support lines of the set X. The thickness of a convex set X is the
minimum of the distance between the two parallel support lines of the set X.
Note that (i) the diameter of any triangle is the length of the longest side, (ii)
the thickness of any triangle is the length of the altitude to the longest side, (iii)
the diameter of any regular hexagon is the length of the diagonal, and (iv) the
thickness of any regular hexagon is the distance between two parallel edges of the