  Single Row Equidistant Facility Layout Problem SREFLP is with an NP-Hard
nature to mimic material handling costs along with equally spaced straight-line
facilities layout. Based on literature, it is obvious that efforts of
researchers for solving SREFLP turn from exact methods into release the running
time tracing the principle of the approximate methods in time race, regardless
searching their time complexity release in conjunction with a provable quality
of solutions. This study focuses on Lower bounding LB techniques as an
independent potential solution tool for SREFLP. In particular, Best-known
SREFLP LBs are reported from literature and significantly LBs optimum scenarios
are highlighted. Initially, one gap of the SREFLP bidirectional LB is enhanced.
From the integration between the enhanced LB and the best-known Gilmore-Lawler
GL bounding, a new SREFLP optimum scenario is provided. Further improvements to
GLB lead to guarantee an exact Shipping/Receiving Facility assignment and
propose a conjecture of at most 4/3 approximation scheme for SREFLP.
