Neighborhood Definition of Limit
Here is a more generic form for the definition of limit of a function
at a point.
Notice that I have jammed both of the phrases "neighborhood E of L" and
"neighborhood D of the point a".
I have also jammed "x belongs to D" and "f(x) belongs to E".
Note that "f(x)" will be vulerable to parsing, hence I write it as "f
of x" inside the jammed form.
Unfortunately the "then" in the last clause got mangled by the parser.