A Relativistic Origin for Early Cosmic Inflation Without an Inflaton Field

This paper proposes a relativistic mechanism for early cosmic accelerated expansion that does not require a fundamental inflaton field. Instead, inflation is interpreted as a high-curvature phase of spacetime in which local proper time is strongly suppressed relative to the global expansion clock. Within the Einstein–Hilbert framework and a homogeneous FRW geometry with a curvature-dependent lapse function, we introduce the Relativistic Inflation via Clock Suppression (RIC) mechanism. We show that this naturally leads to a quasi–de Sitter background with an effective equation of state close to w ≃ −1. Under explicit and transparent assumptions, the resulting background can be embedded in the effective field theory of single-clock inflation, yielding predictions for the scalar spectral index and tensor-to-scalar ratio consistent with Planck and BICEP/Keck observations, while generically predicting a strongly suppressed tensor amplitude. This work serves as a foundational technical component of the Unified Post-Relativistic Framework (UPRF) and provides a geometrical baseline for early-Universe acceleration within General Relativity.