“Thought as” vs. “Thought of as” vs “Thought of as being” [closed]

Which of the following phrases below are correct?

1. The referred maps are to be thought as translations, as means of identifying the tangent spaces.

2. The referred maps are to be thought of as translations, as means of identifying the tangent spaces.

3. The referred maps are to be thought of as being translations, as means of identifying the tangent spaces.

Solution 1:

Both 2 and 3 are used in normal conversation. 1 is incorrect, although "considered translations" would be correct. However, the context appears to be mathematical and, in that case, 2 would probably more appropriate because, being mathematical, the terms "map", "translation" and "tangent space" are all precisely defined.