- #1
embemilyy
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Homework Statement
Prove that |AB[itex]\cup[/itex]C|=|ABx AC| by demonstrating a bijection between the two sets.
Homework Equations
Two sets have equivalent cardinality if there is a bijection between them/
The Attempt at a Solution
Essentially I can prove that there is a function from AB[itex]\cup[/itex]C to ABx AC, defined by <f restricted to B, f restricted to C> but it's only onto if B[itex]\cap[/itex]C=0.
Or I can prove a function the other way but it's only one-to-one if the same condition holds.
Other solutions I've seen online also say that this condition is necessary, but it's not included in the homework question. Any ideas?