[R] Finding (Ordered Subvectors)

[Lorenzo Isella]

Dear All,
Consider a simple example

a<-c(1,4,3,0,4,5,6,9,3,4)
b<-c(0,4,5)
c<-c(5,4,0)

I would like to be able to tell whether a sequence is contained (the 
order of the elements does matter) in another one e.g. in the example 
above, b is a subsequence of a, whereas c is not. Since the order 
matters, I cannot treat the sequences above as sets (also, elements are 
repeated).
Does anyone know a smart way of achieving that?
Many thanks

Lorenzo