Core Structural Layer: Boundary — A Non-Modal Fixation

This paper examines boundary within a non-modal structural framework. Boundary is not treated as limit, separation, edge, or terminal distinction. Instead, it is articulated as failure of retention without transition into another state or collapse into absence. The paper argues that retention is not removed but fails to be maintained, and that connection is not lost but fails to be retained. Boundary is therefore positioned not as discontinuity or disappearance, but as structural failure of maintained retention. Part of the Core Structural Layer within Kasei-Theory, this paper develops a non-modal account of boundary without causality, temporality, or representational mediation.