SIGMA is a refereed online open access journal for publication of papers in the following areas:*Geometrical methods in mathematical physics*Lie theory and differential equations*Classical and quantum integrable systems*Dynamical systems and chaos*Exactly and quasi-exactly solvable models*Lie groups and algebras, representation theory*Orthogonal polynomials and special functions*Quantum algebras, quantum groups and noncommutative geometry*Supersymmetry and supergravity, strings and branes*Cosmology and quantum gravity.