Gauge fields-strings duality and tensionless superstrings

The duality map between gauge theories and strings suggests that when the gauge theory is in the weak coupling regime the dual string tension effectively tends to zero, $\alpha' \to \infty$. This observation of Sundborg and Witten initiates a fresh interest to the old problem of tensionless limit of standard string theory and to the description of its genuine symmetries. We approach this problem formulating tensionless string theory by means of geometrical concept of surface perimeter. The perimeter action uniquely leads to a tensionless string theory.