# Homework Help: Does anyone know if this is true $A \bigcap B^{c} = \emptyset 1. Jan 23, 2012 ### glebovg Does anyone know if this is true [itex]A \bigcap B^{c} = \emptyset \Leftrightarrow A \bigcup B^{c} = U$ ?

2. Jan 23, 2012

### PAllen

Re: Sets

It's obviously false. You should readily be able to find a counter example even for U being a set of cardinality 3.