<p>The classical Hermite–Hadamard inequality states that in any compact interval of <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\mathbb {R}\)</EquationSource> <EquationSource Format="MATHML"><math> <mi mathvariant="double-struck">R</mi> </math></EquationSource> </InlineEquation>, the integral mean of a convex function is greater than the functional value at the midpoint, while it is bounded above by the average of the functional values at the endpoints. This paper presents some generalizations, refinements, and extensions of the Hermite–Hadamard inequality for convex functions. We show that if <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(f\in L[a,b]\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>f</mi> <mo>∈</mo> <mi>L</mi> <mo stretchy="false">[</mo> <mi>a</mi> <mo>,</mo> <mi>b</mi> <mo stretchy="false">]</mo> </mrow> </math></EquationSource> </InlineEquation> is a convex function, then for any <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(p\in (a,b)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>p</mi> <mo>∈</mo> <mo stretchy="false">(</mo> <mi>a</mi> <mo>,</mo> <mi>b</mi> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> the following inequalities are satisfied <Equation ID="Equ22"> <EquationSource Format="TEX">\(\begin{aligned}\begin{aligned} f\bigg (\dfrac{a+2p+b}{4}\bigg )\le \dfrac{1}{2}\bigg (\dfrac{1}{p-a}\int _{a}^p f(z)\,dz+\dfrac{1}{b-p}\int _{p}^b f(z)\,dz\bigg )\le \dfrac{f(a)+2f(p)+f(b)}{4}, \end{aligned} \end{aligned}\)</EquationSource> <EquationSource Format="MATHML"><math display="block"> <mrow> <mtable> <mtr> <mtd columnalign="right"> <mrow> <mtable> <mtr> <mtd columnalign="right"> <mrow> <mi>f</mi> <mrow> <mo maxsize="2.047em" minsize="2.047em" stretchy="true">(</mo> </mrow> <mstyle displaystyle="true" scriptlevel="0"> <mfrac> <mrow> <mi>a</mi> <mo>+</mo> <mn>2</mn> <mi>p</mi> <mo>+</mo> <mi>b</mi> </mrow> <mn>4</mn> </mfrac> </mstyle> <mrow> <mo maxsize="2.047em" minsize="2.047em" stretchy="true">)</mo> </mrow> <mo>≤</mo> <mstyle displaystyle="true" scriptlevel="0"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mstyle> <mrow> <mo maxsize="2.047em" minsize="2.047em" stretchy="true">(</mo> </mrow> <mstyle displaystyle="true" scriptlevel="0"> <mfrac> <mn>1</mn> <mrow> <mi>p</mi> <mo>-</mo> <mi>a</mi> </mrow> </mfrac> </mstyle> <msubsup> <mo>∫</mo> <mrow> <mi>a</mi> </mrow> <mi>p</mi> </msubsup> <mi>f</mi> <mrow> <mo stretchy="false">(</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mspace width="0.166667em" /> <mi>d</mi> <mi>z</mi> <mo>+</mo> <mstyle displaystyle="true" scriptlevel="0"> <mfrac> <mn>1</mn> <mrow> <mi>b</mi> <mo>-</mo> <mi>p</mi> </mrow> </mfrac> </mstyle> <msubsup> <mo>∫</mo> <mrow> <mi>p</mi> </mrow> <mi>b</mi> </msubsup> <mi>f</mi> <mrow> <mo stretchy="false">(</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mspace width="0.166667em" /> <mi>d</mi> <mi>z</mi> <mrow> <mo maxsize="2.047em" minsize="2.047em" stretchy="true">)</mo> </mrow> <mo>≤</mo> <mstyle displaystyle="true" scriptlevel="0"> <mfrac> <mrow> <mi>f</mi> <mo stretchy="false">(</mo> <mi>a</mi> <mo stretchy="false">)</mo> <mo>+</mo> <mn>2</mn> <mi>f</mi> <mo stretchy="false">(</mo> <mi>p</mi> <mo stretchy="false">)</mo> <mo>+</mo> <mi>f</mi> <mo stretchy="false">(</mo> <mi>b</mi> <mo stretchy="false">)</mo> </mrow> <mn>4</mn> </mfrac> </mstyle> <mo>,</mo> </mrow> </mtd> </mtr> </mtable> </mrow> </mtd> </mtr> </mtable> </mrow> </math></EquationSource> </Equation><Equation ID="Equ23"> <EquationSource Format="TEX">\(\begin{aligned} \text{ and } \end{aligned}\)</EquationSource> <EquationSource Format="MATHML"><math display="block"> <mrow> <mtable> <mtr> <mtd columnalign="right"> <mrow> <mspace width="0.333333em" /> <mtext>and</mtext> <mspace width="0.333333em" /> </mrow> </mtd> </mtr> </mtable> </mrow> </math></EquationSource> </Equation><Equation ID="Equ24"> <EquationSource Format="TEX">\(\begin{aligned}\begin{aligned} \begin{aligned}&amp;\sup _{p\in (a,b)}\Bigg [\min \bigg \{f\bigg (\dfrac{a+p}{2}\bigg ),\,\,f\bigg (\dfrac{p+b}{2}\bigg )\bigg \}\Bigg ] \le \dfrac{1}{b-a}\int _{a}^{b} f(z)\,dz\\&amp;\qquad \le \inf _{p\in (a,b)}\Bigg [\max \bigg \{\dfrac{f(a)+f(p)}{2},\,\,\dfrac{f(p)+f(b)}{2}\bigg \}\Bigg ]. \end{aligned} \end{aligned}\end{aligned}\)</EquationSource> <EquationSource Format="MATHML"><math display="block"> <mrow> <mtable> <mtr> <mtd columnalign="right"> <mrow> <mtable> <mtr> <mtd columnalign="right"> <mrow> <mtable> <mtr> <mtd /> <mtd columnalign="left"> <mrow> <munder> <mo movablelimits="true">sup</mo> <mrow> <mi>p</mi> <mo>∈</mo> <mo stretchy="false">(</mo> <mi>a</mi> <mo>,</mo> <mi>b</mi> <mo stretchy="false">)</mo> </mrow> </munder> <mrow> <mo maxsize="2.470em" minsize="2.470em" stretchy="true">[</mo> </mrow> <mo movablelimits="true">min</mo> <mrow> <mo maxsize="2.047em" minsize="2.047em" stretchy="true">{</mo> </mrow> <mi>f</mi> <mrow> <mo maxsize="2.047em" minsize="2.047em" stretchy="true">(</mo> </mrow> <mstyle displaystyle="true" scriptlevel="0"> <mfrac> <mrow> <mi>a</mi> <mo>+</mo> <mi>p</mi> </mrow> <mn>2</mn> </mfrac> </mstyle> <mrow> <mo maxsize="2.047em" minsize="2.047em" stretchy="true">)</mo> </mrow> <mo>,</mo> <mspace width="0.166667em" /> <mspace width="0.166667em" /> <mi>f</mi> <mrow> <mo maxsize="2.047em" minsize="2.047em" stretchy="true">(</mo> </mrow> <mstyle displaystyle="true" scriptlevel="0"> <mfrac> <mrow> <mi>p</mi> <mo>+</mo> <mi>b</mi> </mrow> <mn>2</mn> </mfrac> </mstyle> <mrow> <mo maxsize="2.047em" minsize="2.047em" stretchy="true">)</mo> </mrow> <mrow> <mo maxsize="2.047em" minsize="2.047em" stretchy="true">}</mo> </mrow> <mrow> <mo maxsize="2.470em" minsize="2.470em" stretchy="true">]</mo> </mrow> <mo>≤</mo> <mstyle displaystyle="true" scriptlevel="0"> <mfrac> <mn>1</mn> <mrow> <mi>b</mi> <mo>-</mo> <mi>a</mi> </mrow> </mfrac> </mstyle> <msubsup> <mo>∫</mo> <mrow> <mi>a</mi> </mrow> <mi>b</mi> </msubsup> <mi>f</mi> <mrow> <mo stretchy="false">(</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mspace width="0.166667em" /> <mi>d</mi> <mi>z</mi> </mrow> </mtd> </mtr> <mtr> <mtd columnalign="right"> <mrow /> </mtd> <mtd columnalign="left"> <mrow> <mspace width="2em" /> <mo>≤</mo> <munder> <mo movablelimits="true">inf</mo> <mrow> <mi>p</mi> <mo>∈</mo> <mo stretchy="false">(</mo> <mi>a</mi> <mo>,</mo> <mi>b</mi> <mo stretchy="false">)</mo> </mrow> </munder> <mrow> <mo maxsize="2.470em" minsize="2.470em" stretchy="true">[</mo> </mrow> <mo movablelimits="true">max</mo> <mrow> <mo maxsize="2.047em" minsize="2.047em" stretchy="true">{</mo> </mrow> <mstyle displaystyle="true" scriptlevel="0"> <mfrac> <mrow> <mi>f</mi> <mo stretchy="false">(</mo> <mi>a</mi> <mo stretchy="false">)</mo> <mo>+</mo> <mi>f</mi> <mo stretchy="false">(</mo> <mi>p</mi> <mo stretchy="false">)</mo> </mrow> <mn>2</mn> </mfrac> </mstyle> <mo>,</mo> <mspace width="0.166667em" /> <mspace width="0.166667em" /> <mstyle displaystyle="true" scriptlevel="0"> <mfrac> <mrow> <mi>f</mi> <mo stretchy="false">(</mo> <mi>p</mi> <mo stretchy="false">)</mo> <mo>+</mo> <mi>f</mi> <mo stretchy="false">(</mo> <mi>b</mi> <mo stretchy="false">)</mo> </mrow> <mn>2</mn> </mfrac> </mstyle> <mrow> <mo maxsize="2.047em" minsize="2.047em" stretchy="true">}</mo> </mrow> <mrow> <mo maxsize="2.470em" minsize="2.470em" stretchy="true">]</mo> </mrow> <mo>.</mo> </mrow> </mtd> </mtr> </mtable> </mrow> </mtd> </mtr> </mtable> </mrow> </mtd> </mtr> </mtable> </mrow> </math></EquationSource> </Equation>Alongside these results, for given non-negative convex functions <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(f_1,\ldots , f_n\in L[a,b]\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi>f</mi> <mn>1</mn> </msub> <mo>,</mo> <mo>…</mo> <mo>,</mo> <msub> <mi>f</mi> <mi>n</mi> </msub> <mo>∈</mo> <mi>L</mi> <mrow> <mo stretchy="false">[</mo> <mi>a</mi> <mo>,</mo> <mi>b</mi> <mo stretchy="false">]</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation>, we derive a Hermite–Hadamard-type inequality for their product, incorporating the Beta function. We provide corollaries and comparative results to illustrate the generalizations and effectiveness of our findings. The research background, description of various notions, terminologies, and other crucial details can be found in the Introduction section.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

On generalization, refinement, and extension of Hermite–Hadamard inequality

  • Angshuman R. Goswami

摘要

The classical Hermite–Hadamard inequality states that in any compact interval of \(\mathbb {R}\) R , the integral mean of a convex function is greater than the functional value at the midpoint, while it is bounded above by the average of the functional values at the endpoints. This paper presents some generalizations, refinements, and extensions of the Hermite–Hadamard inequality for convex functions. We show that if \(f\in L[a,b]\) f L [ a , b ] is a convex function, then for any \(p\in (a,b)\) p ( a , b ) the following inequalities are satisfied \(\begin{aligned}\begin{aligned} f\bigg (\dfrac{a+2p+b}{4}\bigg )\le \dfrac{1}{2}\bigg (\dfrac{1}{p-a}\int _{a}^p f(z)\,dz+\dfrac{1}{b-p}\int _{p}^b f(z)\,dz\bigg )\le \dfrac{f(a)+2f(p)+f(b)}{4}, \end{aligned} \end{aligned}\) f ( a + 2 p + b 4 ) 1 2 ( 1 p - a a p f ( z ) d z + 1 b - p p b f ( z ) d z ) f ( a ) + 2 f ( p ) + f ( b ) 4 , \(\begin{aligned} \text{ and } \end{aligned}\) and \(\begin{aligned}\begin{aligned} \begin{aligned}&\sup _{p\in (a,b)}\Bigg [\min \bigg \{f\bigg (\dfrac{a+p}{2}\bigg ),\,\,f\bigg (\dfrac{p+b}{2}\bigg )\bigg \}\Bigg ] \le \dfrac{1}{b-a}\int _{a}^{b} f(z)\,dz\\&\qquad \le \inf _{p\in (a,b)}\Bigg [\max \bigg \{\dfrac{f(a)+f(p)}{2},\,\,\dfrac{f(p)+f(b)}{2}\bigg \}\Bigg ]. \end{aligned} \end{aligned}\end{aligned}\) sup p ( a , b ) [ min { f ( a + p 2 ) , f ( p + b 2 ) } ] 1 b - a a b f ( z ) d z inf p ( a , b ) [ max { f ( a ) + f ( p ) 2 , f ( p ) + f ( b ) 2 } ] . Alongside these results, for given non-negative convex functions \(f_1,\ldots , f_n\in L[a,b]\) f 1 , , f n L [ a , b ] , we derive a Hermite–Hadamard-type inequality for their product, incorporating the Beta function. We provide corollaries and comparative results to illustrate the generalizations and effectiveness of our findings. The research background, description of various notions, terminologies, and other crucial details can be found in the Introduction section.