BinaryTree from BinaryTreeParentArray
The binary tree an in-order parent array describes: a node below its parent goes left, above it right.
Declines an array that isn't one: two roots, two left children, a cycle, or labels out of order.
Called as CombinatorialMap(x, "BinaryTree"). The head's page has its examples.
Also from
The same name out of other carriers, each its own implementation: DyckPath.