Yup, it is. I think I once managed to get out most of the bulbs from an oxalis plant; it was a small one growing in a pile of very loose mulch and I think I still broke off a tendril or two and didn't track them down.

The pages I found online were really quite pessimistic about the possibility of successfully pulling them up. What I gathered is that, if one is really consistently persistent for two or three years, the root-bits will run out of energy....