Can stream entry be reached by focusing on the links in dependent co-arising Can you gain stream entry by focusing on the links in dependent co-arising http://www.accesstoinsight.org/tipitaka/sn/sn12/sn12.002.than.html. 

The buddha says this: "And what is the noble method that is rightly seen and rightly ferreted out by discernment? There is the case where a disciple of the noble ones notices:

When this is, that is.
From the arising of this comes the arising of that.
When this isn't, that isn't.
From the cessation of this comes the cessation of that." 


In reference to dependent co-arising, but I wonder whether it's actually a method.
It depends what you mean by "focussing on". If by that you mean thinking about mentally, then no, that is not possible, since the mind will be focussed on an abstract object and not be able to see impermanence, suffering, and non-self.

If by that you mean observing empirically then yes, since the links are ultimate reality. By focussing on them, you will see impermanence, suffering, and non-self, which is the path of purification, according to the Buddha.