Teacher:Given a text, write a compressed version of it in a single sentence.
Teacher: Now, understand the problem? Solve this instance: Building on work of Astekar and his colleagues, Rovelli and Smolin proceeded directly from general relativity along somewhat familiar pathways of canonical quantization. In outline, general relativity is based on a metric tensor concerning space-time.
Student:
On work of Astekar and his colleagues, proceeded directly from general relativity along pathways of canonical quantization. Relativity is based on a metric tensor concerning space-time.