• Branch-and-bound and implicit enumeration dominated early IP methodology, using tree-search with pruning and surrogate constraints to solve 0-1, knapsack, scheduling, and facility-location problems [6], [17], [8], [19], [18], [5].

• Balas' additive/implicit enumeration lineage, with additive algorithms, Balas’ method, and early cutting ideas (filter/intersection cuts), used to tighten LP relaxations and prune search in 0-1 IP [1], [3], [6], [7], [20].

• Cutting-plane inception and branch-and-cut hybrids appeared, leveraging filter methods and intersection cuts to strengthen relaxations and guide enumeration in IP problems [7], [20], [9].

• Zero-one specific algorithm families emerged: additive algorithms for 0-1 LPs, multiphase-dual strategies, direct search on binary variables, and combinatorial programming formulations [1], [3], [4], [11].

• Canonical combinatorial problems (knapsack, sequencing, scheduling, facility-location) served as standard testbeds for IP methods, stimulating algorithmic development and comparative evaluation [13], [17], [19], [8], [15].