Going on foot, mathematician leaves capital (8)
I believe the answer is:
enduring
'going on' is the definition.
(enduring is a kind of going on)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for enduring that I've seen before include "stable ..." , "Eternal" , "showing toleration" , "Lasting' tolerating" , "Putting up with patiently" .)