This document presents the Level A mathematical foundation of the Simita Universe Model, a unified theoretical framework that connects multilayer time structure, dual scalar-field dynamics, and the Planck membrane formalism into a coherent representation of matter and spacetime. The model introduces three components of time (t₁ – physical time, t₂ – field time, t₃ – cyclic genetic time), two fundamental scalar fields (ΔΦ and ΔΨ), and a linear membrane operator P(x) = a·ΔΦ + b·ΔΨ, which together generate the physical universe through the projection operator (M + S) = k·P. Level A provides a stable, minimal, and academically presentable mathematical base that is logically consistent, difficult to attack, and ready for further extensions toward Level B and Level C, including tensor-based operators and quantum-gravity relations. This release includes the complete English three-part compact PDF version prepared for international publication and indexing.