B General Relativity & Grav. Time Dilation Qn

IXWELL
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hello I'm korean high school student and sorry for my poor English.
I saw ## t_0=t_f\sqrt{1 -\frac{ 2GM}{rc^2}} ## in wikipedia.
does ## \sqrt{1 -\frac{ 2GM}{rc^2}} ## of this equation have name like lorentz factor ## \frac{1}{\sqrt{1 -\frac{v^2}{c^2}}} ##of ## t=\frac{t_0}{\sqrt{1 -\frac{v^2}{c^2}}} ## ?
or is it just called time dilation equation?
I just want to know if there is a word specifically referring to factor ## \sqrt{1 -\frac{ 2GM}{rc^2}} ##.
 
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You can read more about that factor here in the wikipedia article on Gravitational Time Dilation where they use the Lorentz factor and the escape velocity to get the ##\sqrt{1 -\frac{ 2GM}{rc^2}}## factor.

https://en.wikipedia.org/wiki/Gravitational_time_dilation

Here is the LATEX for the factor of interest:
# # \sqrt{1 -\frac{ 2GM}{rc^2}} # #

NOTE: Remove the spaces between "# #" to activate the web page mathjax latex rendering code.

Please take some time to learn LATEX for entering equations here. The cut/paste of images just doesn't work out well. There is a link to LATEX formatting in my signature section at the bottom of this post.
 
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You might call it the gravitational time dilation factor or the gravitational red shift factor. It doesn’t really have a name because it wasn't an independent discovery like the Lorentz factor, it's just a part of Schwarzschild's solution of Einstein's equations. It's also not particularly general because gravitational time dilation is only really applicable in some circumstances - it cannot be defined for things like a pair of orbiting black holes, for example
 
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