Bitcoin halving is the process where the block reward for mining new blocks is cut in half. This happens every 210,000 blocks, or approximately every four years. The next halving is set to occur in May 2020. This event has been seen as a positive by many in the Bitcoin community because it reduces inflation and could lead to an increase in the price of Bitcoin.
However, there are also some negatives to consider, such as the potential for a decrease in hashrate and difficulty if the price of Bitcoin does not increase. Overall, the halving is a positive event that should be watched closely by those invested in Bitcoin.