Therefore, we will avoid using, as much as possible, most of the equations known in modern physics. We do not challenge any of the mathematical equations of modern physics. The usual aspect of physics, as being a computational device for predicting the outcomes of possible measurements, is not considered here at all. In this book, we consider only the second aspect of physics. Yes, there are in physics some elements that do not exist in mathematics.
Physics deals with concepts such as mass, length, time and energy.
These concepts correspond in our mind to images different from the ones represented by mathematical relations. They have a different representation in our mind because they must be submitted to external tests. They have to comply with observational results. There is no equivalence in mathematics. A mathematical demonstration never implies any experimentation.