LinearOrders Formalization of results regarding linear orders in Lean. Main Theorems Formalized Theorem (Finite Left Cancellation) If $X$ and $Y$ are linear orders, $n \in \mathbb{N}$, and $nX \cong nY$, then $X \cong Y$. Theorem (Lindenbaum) If $X$ and $Y$ are linear orders such that $X$ embeds in an initial segment of $Y$ and $Y$ embeds in a final segment of $X$, then $X \cong Y$. Here are the high level proofs that parallel how the proofs are formalized.