Mitsubishi? No, simply unrelated competitors.
I think for the US market, Mitsubishi is the builder of tractors sold (and supported) here under other labels. Maybe Mahindra-marketed tractors, for example, and some other brands in the past. Those are excellent quality but not related to Yanmar.
If someone is trying to tell you that the tractor you found 'is the same as a Yanmar' ... run away.