What is Sleeping Beauty problem in decision theory

This refers to a puzzle about the probabilities of a tossed coin landing heads up and tails up. According to it, Sleeping Beauty, the popular fairytale character, is first put to sleep by researchers on a Sunday. A coin is then tossed and Sleeping Beauty is woken up on Monday if it lands heads up. However, if the coin lands tails up, she is put back to sleep on Monday with her memory erased and woken up the next day. At the end of the experiment, Sleeping Beauty is asked about the probability of the coin having landed heads and tails up. Some have argued that the probabilities are equal; others say the coin landing heads up is more likely.

Source: The Hindu, 24/082018