= Solution
The active prefix of the <array> must represent a complete $d$-ary tree, filled in the prescribed order, and must obey <heap order>:
$$
\boxed{A[\operatorname{Parent}(i)]\leq A[i]
\quad\text{for every }1\leq i<A.\text{heap-size}}.
$$
Equivalently, every parent is no larger than each existing child. Repeatedly following parents shows that the root contains a global minimum. The array representation already provides the complete-tree shape; it is not enough to check only that the root is a minimum, since the inequality must hold throughout the <d-ary min-heap>. Assume integral $d\geq2$ throughout the heap operations.
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