[□=□]
[lemma=□]
The NAG C Library contains many mathematical and statistical routines which are useful for software developers . Control theory is a discipline of critical importance with a rich and beautiful mathematical structure that is at the heart of traditional engineered system design . However , before one undertakes a calculation one knows a lot of " prior information " : general mathematical , physical and statistical principles provide information about what kinds of solutions are likely to appear , and scaling laws and sheer experience provide other hints . This is why they have difficulties with the times tables and different mathematical operations . He found this divine beauty not simply in the magic of theatre , but in the poetry of words , in a mathematical formula ; and perhaps supremely , in the human form ; in the body-images that moved him .