Converts an monotone triangle to an alternating sign matrix (ASM) according to the bijection described in [HR]. More precisely, suppose $T=(T_0,\ldots,T_n)$ is a monotone triangle. The unique ASM $A$ corresponding to $T$ is given by $A_m = \mathbb{1}_{T_m}  \mathbb{1}_{T_{m1}}$, where $A_m$ denotes the $m$th row of $A$ and $\mathbb{1}_{T_i}$ is the is a vector of length $n$ whose entries are $1$ in the positions whose indices appear in $T_i$ and $0$ otherwise. See [HR] for more details.
This function does not check that what you've given it is actually a monotone triangle before attempting to convert to an ASM.


The object monotoneTriangleToASM is a method function.