READING: I §3 10
Back to reading:
I §3 9
begin quote ita"
CHAPTER I [:] Notions from Set Theory [...] §3. FUNCTIONS. "end quote
These pages assume that the reader has the book and is reading along. topic index contents
Please read these notes from the beginning to here and then paragraph 8 of §3.
THE IMAGE OF A SET UNDER A FUNCTION
If f : X → Y is a function and X X, then the subset of Y given by
There is always danger of confusion when I am the reader, but this seems clear enough.
Now, after you read the next quote, replace the x by a, let aX, and read the equation again without the "for each" part.
begin quote ita-1-3-7-pg10 "
The two uses we have made for the symbol f ( ) are related by the equation