+118609 What is xED(f)*backwards E* f(x)=6 mean?
\(xED(f)*\ni* f(x)=6\)
\(\ni \text{ means owns, or has member} \)
ref:
https://oeis.org/wiki/List_of_LaTeX_mathematical_symbols#Relation_operators
I think this is what you are describing ?? but I don't know what it means.
+33616 Might be:
or:
if D stands for domain, this could mean something like: "the set of x's belonging to the domain of the function f implies that there is an f(x) equal to 6".
+118609 Thanks Alan, but could you please expand upon the meaning of this. Or give an example maybe.
This is just an if/then that applies to a specific function f, isn't it? 
I really do not understand well at all :(
\(x\in D(f) \cdot \ni\cdot f(x)=6\)
+33616 Well, I'm not sure I understand it myself!
The first part says x is a member of D(f), though we're not told what D(f) means. I guessed it means the Domain of a function f.
The backward, upper case E, means "there exists", so I simply guessed the whole thing means: if x is the set of variables in the domain of f there exists a specific value of x such that f(x) equals 6.
Still doesn't make a lot of sense though!!
