While fixing my notation in a research article, I want to write something like this:
Let A be a line and (let) B (be) a plane.
Question: Do I have to write the second let and be or can I omit one or both of them?
(The context is a research article in mathematics, if this should matter. In fact, I do not talk about lines and planes there, but use these terms here in the hope to make the phrase more accessible to non-mathematicians.)