is advice function and an oracle the same thing? In the context of P/poly complexity class, an advice function is mentioned.
How is the advice function different than an oracle(/certificate)?
https://en.wikipedia.org/wiki/Advice_(complexity)
https://en.wikipedia.org/wiki/P/poly
No, they are not the same.  An oracle is something that an algorithm can send inputs to, and get back outputs, possibly many times.  Advice is a single value that is provided to the algorithm, and depends only on the length of the input to the algorithm.