Let
·be a sequence of k -dimensional i.i.d. random vectors and define the first-passage times
for
where (cvτ)v, τ= 1,· ··,k is the covariance matrix of
In this paper the weak convergence of Zn in (D[0, ∞))k is proved under the assumption
(0,∞) for all v = 1, ···, k. We deduce the result from the Donsker invariance principle by means of Theorem 5.5 of Billingsley (1968). This method is also used to derive a limit theorem for the first-exit time Mn = min{Nnt
for fixed t1,···, tk > 0. The second result is an extension of a theorem of Hunter (1974) whose method of proof applies only if Ρ (ξ1
[0,∞)k) = 1 and μ ν = tv for all v = 1, ···, k.