What rule gives a special allowance to teachers and students?

There isn't one single, universally applicable rule that gives a special allowance *to all* teachers and students. The allowances vary significantly depending on jurisdiction (country, state, etc.) and the specific context (e.g., tax laws, copyright laws, library regulations).

However, some examples of rules that *may* provide special allowances to teachers and students include:

* Copyright laws: Many countries have "fair use" or "fair dealing" exceptions to copyright that allow teachers and students to use copyrighted material for educational purposes, such as showing a short video clip in class or making copies of articles for a class assignment. However, the specifics of what constitutes fair use are strictly defined and vary by jurisdiction.

* Tax laws: Some countries offer tax deductions or credits for educational expenses, benefiting both teachers (for professional development) and students (for tuition or supplies). These vary greatly depending on the country and its tax system.

* Library regulations: Libraries often have different borrowing policies or access privileges for teachers and students, granting them extended loan periods or access to specialized resources.

* Public transportation: Some areas may offer discounted or free public transportation to students.

In short, there's no single "rule," but various laws, regulations, and policies offer specific allowances to teachers and students in different contexts. To find specific allowances, one must look at the relevant laws and regulations of the specific jurisdiction.