The study of L-functions is a testament to the power of abstraction in mathematics.
When making something， always get a few extras — extra material， extra parts， extra space， extra finishes. The extras serve as backups for mistakes， reduce stress， and fill your inventory for the future. They are the cheapest insurance.
钢铁行业必须拥抱可持续性，否则就有被淘汰的风险。