$S_1$, $S_2$, $S_3$, and $S_4$ are the areas of the four faces.
We know that a triangle has a condition for their edges $a$, $b$, $c$, so all edge length must satify
$$|a-b|<c<a+b$$ or $$|a-c|<b<a+c$$ or $$|b-c|<a<b+c$$
Is there any such limitations for a tetrahedron?
It is obvious that upper limit is
What is the lower limit condition for a tetrahedron as we have for a triangle $|a-b|<c$? How can the lower limit condition of a surface on a tetrahedron be defined by other surfaces such as $f(S_2,S_3,S_4)<S_1<S_2+S_3+S_4$
Thanks for answers