Let R \mathbb{R} R be the real numbers , an ordered field with order ≤ \le ≤ , write ∣ t ∣ |t| ∣ t ∣ for the absolute value of t ∈ R t\in\mathbb{R} t ∈ R and t − 1 t^{-1} t − 1 for the multiplicative inverse of t ≠ 0 t\ne 0 t = 0 , and let exp \exp exp be the exponential function . Let p p p be a polynomial function on R \mathbb{R} R .
Then the following hold.
1. (Decay at + ∞ +\infty + ∞ ) For every ε ∈ R \varepsilon\in\mathbb{R} ε ∈ R with 0 < ε 0<\varepsilon 0 < ε there is M ∈ R M\in\mathbb{R} M ∈ R with 1 ≤ M 1\le M 1 ≤ M such that
∣ p ( t ) ∣ exp ( − t ) < ε for every t ∈ R with M ≤ t . |p(t)|\exp(-t)<\varepsilon\qquad\text{for every }t\in\mathbb{R}\text{ with }M\le t. ∣ p ( t ) ∣ exp ( − t ) < ε for every t ∈ R with M ≤ t .
2. (Decay at 0 0 0 from the right) For every ε ∈ R \varepsilon\in\mathbb{R} ε ∈ R with 0 < ε 0<\varepsilon 0 < ε there is δ ∈ R \delta\in\mathbb{R} δ ∈ R with 0 < δ 0<\delta 0 < δ such that
∣ p ( s − 1 ) ∣ exp ( − s − 1 ) < ε for every s ∈ R with 0 < s < δ . \bigl|p\bigl(s^{-1}\bigr)\bigr|\exp\bigl(-s^{-1}\bigr)<\varepsilon\qquad\text{for every }s\in\mathbb{R}\text{ with }0<s<\delta. p ( s − 1 ) exp ( − s − 1 ) < ε for every s ∈ R with 0 < s < δ .