People write a lot and sometimes incorrectly. Unfortunately, the paper, web sites, they hold everything.

In your opinion, what is more correct ?

"equation for energy E" or "equation of energy E"

"based on the assumption for high Re number" or "based on the assumption of high Reynolds num"

It's incredible how many different things I can find on the web.

Hello Srdjan

"The equation for X" means "the equation used for obtaining X", whereas "the equation of X" is "the equation pertaining to X".

  • The equation for the total energy is E=mgh+mv^2/2.

  • The equation of motion is given by F=m(dv/dt).

  • As to "assumption", I would use "assumption of X" when I mean "assuming X".

    • The equation could be derived under the assumption of high Re number flow.

    [PS] I think this thread should be moved to "General Sci and Tech English".
Ciao Paco,

What you have written has a lot of sense and sounds pretty fine to me. Some natives gave me very different opinions what a possible answer should be. It has been like...
UK people prefer "of" to "for" and Americans are more free about language, so they would opt for the latter.

Anyway, you gave a good idea to think over, it really looks convincing.