## Min heap#

[…] for any given node C, if P is a parent node of C, then […] the key of P is less than or equal to the key of C.

$$P \le C \;\forall\; C \;|\; P\;\text{is parent of}\;C$$

## Max heap#

[…] for any given node C, if P is a parent node of C, then the key (the value) of P is greater than or equal to the key of C

(“Heap (Data Structure)” 2022)

$$P \ge C \;\forall\; C \;|\; P\;\text{is parent of}\;C$$