Can anyone think of a set of strings for A, B, and C that will disprove the following?

$$(AB) \subseteq (AC) \rightarrow (B \subseteq C)$$

(The sets next to each other means concatenation, ie, AB means A concatenated by B)

Question

Can anyone think of a set of strings for A, B, and C that will disprove the following? 

$$(AB) \subseteq (AC) \rightarrow (B \subseteq C)$$

(The sets next to each other means concatenation, ie, AB means A concatenated by B)

anonymous · Answer

I know this is technically computer science but the CS section seems pretty inactive and the problem is pretty mathematical by nature.

anonymous · Answer

To make it easier to understand, B cannot be a subset of C but when each set is concatenated by A then the results make them a subset.

zarkon · Answer

take A to be the empty set