Sorry if this is not the right place to ask. In the proof of a theorem, I basically want to write $A<B$, and $B=C$, thus $A<C$ as a chain of inequalities. I am not sure if there is a convention to do so: shall I write \begin{align*} A & < B \\ & = C \end{align*} or \begin{align*} A & < B \\ & < C \end{align*}?
In other words, does the second row of the chain refer to the relationship between $A$ and $C$, or to the relationship between $B$ and $C$? I would prefer not repeating $A$ because it is a long expression in my case. Thank you very much in advance.
The second row would be understood to refer to the relationship between $B$ and $C$, so \begin{align*}A&<B\\ &=C\end{align*} would be the proper way of writing this.