## 31 The Equation d*Q* i= *T* · d*S* is form-invariant

Following sections **8** and **12** of the first part of this treatise, the product *T* · d*S* jnecessarily transforms the same way as *T* · *k* , that is by multiplication by the root factor. In **26** and **27** we established d*Q'* = d*Q* · √ and hence the relation

*T · *d*S* j = d*Q *or d*S *= d*Q */* T*

is form-invariant too, independant of our option in favour of temperature or entropy to be relativistically invariant. This result has been announced in section **14** .

We did *not suppose* the invariance of this relation. The invariance is the result of our investigations on the transformations of *k · T* and heat quantities *Q* . In section **34** we will present some further relations between *T* and d*S* jincluding the notion of molar heat capacities.