/-
Copyright (c) 2026 Joseph Tooby-Smith. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Joseph Tooby-Smith
-/modulepublicimportMathlib.Algebra.MvPolynomial.BasicpublicimportMathlib.Algebra.MvPolynomial.CommRingpublicimportMathlib.Tactic.Ring
Charge balancing for polynomials
If the variables of a polynomial carry charges under a phase (here a single element c of infinite
order), then invariance under the simultaneous phase rotation Xᵢ ↦ c^{wᵢ} Xᵢ forces every
monomial to be charge balanced (net charge zero). This is the algebraic content of the statement
that a gauge invariant potential, restricted to a slice on which the gauge torus acts diagonally,
can only contain charge-balanced monomials.
@[expose]publicsection
Charge balancing. If each variable Xᵢ carries an integer charge w i, c is a phase of
infinite order, and the polynomial f is invariant under the charge rotation
Xᵢ ↦ c^{wᵢ} Xᵢ, then every monomial with nonzero net charge has vanishing coefficient.