This paper fixes simultaneity as non-unique under ordering within a non-modal structural system. Simultaneity is not introduced as coincidence in time and is not defined by a shared temporal frame. Time is fixed as ordering of reading, and ordering does not determine a unique configuration. Multiple orderings are fixed under identical structural conditions. Simultaneity is defined as the absence of a uniquely determined ordering. Non-uniqueness does not denote variation or change but the structural absence of uniqueness. No subject, meaning, measurement, comparison, or causality is introduced. The paper isolates the condition under which simultaneity is fixed as non-unique without assuming temporal coincidence or a common frame.
Juza Minamikata (Sat,) studied this question.