The Origin of Mass in the Sub-Envelope-Surface World within the Symmetric Envelope Interface Chain

Within the framework of the Symmetric Envelope Interface Chain, mass is defined as the rate of change of proper time with respect to coordinate time: d = ds/dt. The parent layer and the child layer each have their own d: the parent layer's d_parent = ds_parent/dt_parent varies with phase angle, while the child layer's d_sub = ds_sub/dt_sub remains constant under the child layer's ruler. The child-layer observer defines mass using his own dt_sub and ds_sub, and therefore cannot read the variation of the parent layer's d_parent. The mass formulas of the parent and child layers are constructed in the same way, but belong to different layers; after normalization, they are equal at the dimensionless level, but have different dimensions. Keywords: Symmetric Envelope Interface Chain; sub-envelope surface; mass; proper time; coordinate time; radial velocity; projection layer