What's going on with those alliances in the Tech sphere?

[ProperFerret]

I may seem clueless but it seems like there's always a new development in the AI race. First, there was and I quote from Forbes.com, "Google and Facebook announced a partnership to enable the open-sourced machine learning framework PyTorch to work with Tensor-Processing Units (TPUs)."
Now, I am reading that Microsoft is rallying with Facebook on PyTorch.
So which one is it? Is there a monopoly or a competition among those three?