May 23rd, 2014, 07:54 AM  #1 
Member Joined: Jan 2012 Posts: 51 Thanks: 1  image and inverse image
f : X → Y and A,B subsets of X and Y. I can't see why f(f −1(B)) ⊆ B and not f(f −1(B)) = B in all cases. Can someone help ? I would like to see it with Venn diagram and with a proof. 
May 23rd, 2014, 12:27 PM  #2 
Senior Member Joined: Dec 2013 From: Russia Posts: 327 Thanks: 108 
This happens when $B\setminus\text{image}(f)\ne\emptyset$.


Tags 
image, inverse 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Find the image  WWRtelescoping  Complex Analysis  3  February 24th, 2014 05:24 AM 
Another Find the image  WWRtelescoping  Complex Analysis  2  February 23rd, 2014 08:14 AM 
direct image inverse image  shine123  Linear Algebra  4  November 22nd, 2012 07:35 AM 
Please explain how the set of the inverse image of G was fou  phillyolly  Real Analysis  1  August 28th, 2010 02:57 PM 
continuous map and image  NoSoup4u  Real Analysis  3  October 30th, 2008 06:12 PM 