It implies the existence of a quantity called the entropy of a thermodynamic system. The volume entropy and associated form a close analogy to thermodynamic entropy and temperature. There exist criticisms of the link between thermodynamic entropy and information entropy. The statistical definition of entropy and other thermodynamic properties were developed later. The question of the link between information entropy and thermodynamic entropy is a debated topic. There are mathematical techniques for estimating the entropy of a sequence of symbols. It is a spontaneous process of radiative distribution of entropy. The paper is also the first equation of negative entropy and information. T-symmetry implies the conservation of entropy. Information gain is based on the concept of entropy and information content from information theory. The output is compressed with entropy encoding. Thus the Fisher information represents the curvature of the relative entropy. We now impose the constraint that the entropy be extensive. There are many irreversible processes that result in an increase of the entropy. This formula is usually referred to as the continuous entropy, or differential entropy.