  There are currently two main, continuum models of entropy: a 'reversible',
Clausius entropy model and an 'irreversible', Onsager-Prigogine entropy model.
It is shown that the equations of the 'reversible' and the 'irreversible'
entropy models are equivalent with respect to entropy accumulation, which
entails same values of entropy change and, thus, same values of entropy. The
equivalence contradicts the 'second fundamental equation' of the 'reversible'
entropy model, dS = dQ/T, holding true for 'reversible' phenomena, only. The
equivalence conforms with entropy history independence, which entails that
equation dS = dQ/T must hold true for not 'reversible' phenomena, also. Several
examples, e.g. by commercial engineering software, show that equation dS = dQ/T
holds true for not 'reversible' phenomena, also. The two results of this
analysis, the equivalence of the two entropy models and the falsity of
'reversibility', would be falsified by evidence for equation dS = dQ/T not
holding true for not 'reversible' phenomena. No such evidence has been
presented. The main consequence of the equivalence of the two entropy models is
a signification simplification of the language used in the context of entropy
modeling.
