When the king depends upon only three of the four parts of the science of punishment leaving out a fourth, the age called Treta sets in.
दण्डनीत्यां यदा राजा त्रीनंशाननुवर्तते। चतुर्थमंशमुत्सृज्य तदा त्रेता प्रवर्तते॥