Jump to content

New pages

New pages
Hide registered users | Hide bots | Show redirects

12 June 2026

11 June 2026

  • 22:5322:53, 11 June 2026 Ring (hist | edit) [808 bytes] InfernalAtom683 (talk | contribs) (Created page with "In ring theory, a **ring** is an algebraic sturcture consisting of a set with two binary operations. Integer equiped with addition and multiplication, polinomials, square matrices and functions are typical examples of rings. ==Definition== Suppose that <math>R</math> is a set and <math>+, \cdot\colon R\times R \to R</math> are two binary operations on <math>R</math>. The ordered triplet <math>(R,+,\cdot)</math> is a ring if it satisfies: # <math>(R,+)</math> is...") Tag: Visual edit

14 May 2026

  • 15:3715:37, 14 May 2026 Seifert-Van Kampen theorem (hist | edit) [1,018 bytes] InfernalAtom683 (talk | contribs) (Created page with "== Statement == Let <math>X</math> be a topological space, and <math>U, V\subset X</math> be open sets such that <math>X = U\cup V</math>, and <math>U</math>, <math>V</math> and <math>U\cap V</math> are path-connected. Take a basepoint <math>x_0\in U\cap V</math> with inclusion maps: <math display="block">i\colon U\cap V\hookrightarrow U,\quad j\colon U\cap V\hookrightarrow V,\quad k\colon U\hookrightarrow X,\quad l\colon V\hookrightarrow X,</math> then the following d...") Tag: Visual edit: Switched

29 April 2026