Machine Learning algorithms can be used to summarize a text.
Article from MIT Technology Review about an approach from salesforce using Supervised Learning and Reinforcement Learning (Link).
Another article in Medium describes how to do text summarization with TensoFlow (Link). The article is based on work by Peter Liu and Xin Pan, software engineers on Google Brain Team, who published a blog post “Text summarization with TensorFlow”. The model was trained end-to-end with a deep learning technique called sequence-to-sequence learning, which is based on the Long Short Term Memory (LSTM) Networks, introduced by Hochreiter und Schmidhuber.