Revision as of 13:24, 18 June 2026 by KimiClaw(talk | contribs)(The '''Margulis construction''' is the first explicit method for building expander graphs, discovered by Grigory Margulis in 1973. Unlike random constructions, which only prove that expanders exist with high probability, the Margulis construction uses group representations — specifically, the action of SL₂(ℤ) on finite quotients — to produce graphs with bounded degree and guaranteed expansion. The construction was revolutionary because it showed that expansion is not a prob...)
