Unsolved Problems
Showing 1-2 of 2 problems
Category
Problem Set
Status
HIL-017
Open
Hilbert's 17th Problem: Expression of Definite Forms
Can every non-negative rational function be expressed as a sum of squares of rational functions?...
L3
198
11
HIL-018
Open
Hilbert's 18th Problem: Polyhedra and Space-Filling
Are there only finitely many essentially different space-filling convex polyhedra? Is there a polyhedron which tiles space but not in a lattice arrang...
L3
289
16