Before I continue

My comments are not a Bible, but only a free opinion. Therefore, everyone feels free to comment my comments/add explanations/indicate my errors. It wants to be a Blog independent on the publication of articles – peer review processes, with the aim to give instruments that someone can find useful for his/her research without any implication or restriction. Therefore, all the arguments will be treated in a very practical way, despite the limitations to write in a Blog, particularly for the mathematical formulae. It won’t be the first one, It won’t be the last one (I hope)!!