SIFR

SIFR (arabi— kholi, hej), nul, nol, adadsst, ki hangomi har guna adadro bo on jam kardan on adad tagyir nameyobad. Sifrro bo 0 ishorat mekunand. Hosili zarbi adadi dilkhoh ba 0 Sifr ast: a * 0 = 0 *a = 0. Agar hosili zarbi du adadi haqiqi yo du adadi kompleksi ba Sifr barobar boshad, on goh loaqal yake az hamgarbho ba Sifr barobar ast; az a- = 0 barmeoyad, ki yo a = 0 va yo 6 = 0. Taqsim ba Sifr imkonnopazir ast. Dar matematika mafhumi Sifr baroi yagon majmui elementho (guru, jala, maydon va gayra) niz istifoda meshavad. Dar guruhi kommutativii adaptivi Sifr gufta elementi 0-ro menomand, ki baroi on a + 0 = 0 + a = a ast (in jo a elementi dilkhohi guruh meboshad). Sifr dar halqa niz hamin tavr muayyan karda meshavad; dar on baroi Sifr barobarii a-0 = 0*a = 0 hamesha ijro khohad shud.