Category and group rings in homotopy theory
Category and group rings in homotopy theory
It frequently arises in algebraic topology that a function <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="beta colon upper G right-arrow upper H"> <mml:semantics> <mml:mrow> <mml:mi>β<!-- β --></mml:mi> <mml:mo>:</mml:mo> <mml:mi>G</mml:mi> <mml:mo stretchy="false">→<!-- → --></mml:mo> <mml:mi>H</mml:mi> </mml:mrow> <mml:annotation encoding="application/x-tex">\beta :G \to H</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, between two groups, is not a homomorphism. We show …