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QuantumInfo.ClassicalInfo.ForMathlib.Analysis.SpecialFunctions.Log.NegMulLog

3 declarations

theorem

xlogx-x \log x is strictly increasing on [0,e1][0, e^{-1}]

#negMulLog_strictMonoOn

The function f(x)=xlogxf(x) = -x \log x is strictly monotonically increasing on the closed interval [0,e1][0, e^{-1}].

theorem

xlogx-x \log x is strictly decreasing on [e1,)[e^{-1}, \infty)

#negMulLog_strictAntiOn

The function f(x)=xlogxf(x) = -x \log x (with f(0)=0f(0)=0) is strictly decreasing on the interval [e1,)[e^{-1}, \infty). Here, exp(1)\exp(-1) denotes the value e1e^{-1}, and `Set.Ici` denotes the left-closed infinite interval starting from that point.

theorem

xlogxe1-x \log x \le e^{-1} for x0x \ge 0

#negMulLog_le_rexp_neg_one

For any real number x0x \ge 0, the function xlogx-x \log x (denoted as `negMulLog x`) satisfies the inequality xlogxe1-x \log x \le e^{-1}.