Please define "time vector" - do you mean that the numbers should simply be monotonically increasing? or do you also have a certain "time format" / "time pattern" you're looking for ? If it's the first option, the solution is simple enough:
function out = is_monotonically_increasing(vector)
if sum (vector(2:end) - vector(1:end-1) <= 0) > 0
Out = 0;
else
Out = 1;
end
end
If you need something more specific please describe more thoroughly
