Capable of it or capable of learning it when it's needed? I had to brush up on linear algebra for some problems at work about 2 years ago. I solved the problem,

Capable of it or capable of learning it when it's needed? I had to brush up on linear algebra for some problems at work about 2 years ago. I solved the problem, documented everything properly, and the code has been running unchanged and without issue ever since. In the time between then and now I've definitely lost that knowledge _yet again_.