birthday problem

Summary

birthday problem is a mathematical problem^[1]. It ranks in the top 2% of mathematical_problem entities by monthly Wikipedia readership (2,139 views/month).^[2]

Key Facts

• birthday problem's image is recorded as Birthday Paradox.svg^[3].
• birthday problem's image is recorded as Birthday Paradox-ru.svg^[4].
• birthday problem's image is recorded as Születésnap-paradoxon.svg^[5].
• birthday problem's image is recorded as Birthday Paradox IT.svg^[6].
• birthday problem's image is recorded as Paradoxe anniversaire.svg^[7].
• birthday problem's image is recorded as Birthday paradox chart PL.png^[8].
• birthday problem's image is recorded as Birthday Paradox ua.svg^[9].
• birthday problem's image is recorded as Probabilidade paradoxo do aniversário.svg^[10].
• birthday problem's instance of is recorded as mathematical problem^[11].
• birthday problem's Commons category is recorded as Birthday paradox^[12].
• birthday problem's Freebase ID is recorded as /m/0jp97^[13].
• birthday problem's main subject is recorded as probability^[14].
• birthday problem's described by source is recorded as Security Engineering: A Guide to Building Dependable Distributed Systems, 2nd edition^[15].
• birthday problem's Encyclopædia Britannica Online ID is recorded as topic/birthday-problem^[16].
• birthday problem's defining formula is recorded as \begin{align} \bar p(n) & = 1 \times \left(1-\frac{1}{365}\right) \times \left(1-\frac{2}{365}\right) \times \cdots \times \left(1-\frac{n-1}{365}\right) \ &= { 365 \times 364 \times \cdots \times (365-n+1) \over 365^n } \ &= { 365! \over 365^n (365-n)!} = \frac{n!\cdot{365 \choose n}}{365^n} = \frac{_{365}P_n}{365^n}\end{align}^[17].
• birthday problem's MathWorld ID is recorded as BirthdayProblem^[18].
• birthday problem's Quora topic ID is recorded as Birthday-Problem^[19].
• birthday problem's Rosetta Code page ID is recorded as Birthday_problem^[20].
• birthday problem's maintained by WikiProject is recorded as WikiProject Mathematics^[21].
• birthday problem's Microsoft Academic ID is recorded as 152865758^[22].
• birthday problem's Brilliant Wiki ID is recorded as birthday-paradox^[23].
• birthday problem's ProofWiki ID is recorded as Birthday_Paradox^[24].
• birthday problem's Namuwiki ID is recorded as 생일 문제^[25].
• birthday problem's Metamath statement ID is recorded as birthday^[26].

Body

Works and Contributions

Things named for birthday problem include birthday attack^[27], a type of cryptographic attack^[28].

Why It Matters

birthday problem ranks in the top 2% of mathematical_problem entities by monthly Wikipedia readership (2,139 views/month).^[2] It has Wikipedia articles in 26 language editions, a strong signal of global cultural recognition.^[29] It is known by 31 alternative names across languages and contexts.^[30]

Entities named for it include birthday attack^[27], a type of cryptographic attack^[28].