Bessel's inequality

Summary

Bessel's inequality is a theorem^[1]. It draws 93 Wikipedia views per month (theorem category, ranking #200 of 1,306).^[2]

Key Facts

• Bessel's inequality's instance of is recorded as theorem^[3].
• Friedrich Bessel is named after Bessel's inequality^[4].
• Bessel's inequality's Freebase ID is recorded as /m/05278d^[5].
• Bessel's inequality's defining formula is recorded as \sum_{k=1}^{\infty}\left\vert\left\langle x,e_k\right\rangle \right\vert^2 \le \left\Vert x\right\Vert^2^[6].
• Bessel's inequality's MathWorld ID is recorded as BesselsInequality^[7].
• Bessel's inequality's maintained by WikiProject is recorded as WikiProject Mathematics^[8].
• Bessel's inequality's Microsoft Academic ID is recorded as 59037737^[9].
• Bessel's inequality's Encyclopedia of Mathematics article ID is recorded as Bessel_inequality^[10].
• Bessel's inequality's Lex ID is recorded as Bessels_ulighed^[11].
• Bessel's inequality's OpenAlex ID is recorded as C59037737^[12].

Why It Matters

Bessel's inequality draws 93 Wikipedia views per month (theorem category, ranking #200 of 1,306).^[2] It has Wikipedia articles in 17 language editions, a strong signal of global cultural recognition.^[13] It is known by 6 alternative names across languages and contexts.^[14]