> The worst case scenario is that they are not defined immediately next to the equation and presume that you have read the preceding material.
The textbooks I have used written by Russian mathematicians are almost entirely equation after equation of "explanation", derived from previous equations with the exact transformations in between left as an exercise for the reader.
There's a very distinct cultural difference for sure, but that doesn't make these textbooks less real.
Edit, to clarify: A lot of terms are not explained in natural language either as their very definition is an equation of other terms (feel free to apply recursively).
The textbooks I have used written by Russian mathematicians are almost entirely equation after equation of "explanation", derived from previous equations with the exact transformations in between left as an exercise for the reader.
There's a very distinct cultural difference for sure, but that doesn't make these textbooks less real.
Edit, to clarify: A lot of terms are not explained in natural language either as their very definition is an equation of other terms (feel free to apply recursively).