Physlib

Physlib.QFT.QED.AnomalyCancellation.ConstAbs

Charges assignments with constant abs

We look at charge assignments in which all charges have the same absolute value.

32 declarations

definition

Condition for equal absolute values ∣q1∣=∣q2∣|q_1| = |q_2| for rational numbers

For a pair of rational numbers (q1,q2)∈Q×Q(q_1, q_2) \in \mathbb{Q} \times \mathbb{Q}, this proposition represents the condition that their squares are equal, q12=q22q_1^2 = q_2^2. This is equivalent to the condition that the two rational numbers have the same absolute value, ∣q1∣=∣q2∣|q_1| = |q_2|.

definition

Constant absolute value condition ∣Si∣=∣Sj∣|S_i| = |S_j| for charges

For a charge assignment S∈QnS \in \mathbb{Q}^n within a pure U(1)U(1) gauge theory with nn fermions, this proposition states that all charges have the same absolute value. Formally, it is defined as the condition that for all indices i,j∈{0,1,…,n−1}i, j \in \{0, 1, \dots, n-1\}, the charges satisfy (Si)2=(Sj)2(S_i)^2 = (S_j)^2, which is equivalent to ∣Si∣=∣Sj∣|S_i| = |S_j|.

theorem

Permutations Preserve Constant Absolute Values of Charges

In a pure U(1)U(1) gauge theory with nn fermions, let S=(S0,S1,…,Sn−1)∈QnS = (S_0, S_1, \dots, S_{n-1}) \in \mathbb{Q}^n be a charge configuration. For any permutation σ\sigma in the symmetric group SnS_n, the permuted charge configuration σ(S)=(Sσ(0),Sσ(1),…,Sσ(n−1))\sigma(S) = (S_{\sigma(0)}, S_{\sigma(1)}, \dots, S_{\sigma(n-1)}) has constant absolute values (i.e., ∣Sσ(i)∣=∣Sσ(j)∣|S_{\sigma(i)}| = |S_{\sigma(j)}| for all i,ji, j) if and only if the original configuration SS has constant absolute values (i.e., ∣Si∣=∣Sj∣|S_i| = |S_j| for all i,ji, j).

theorem

Sorting Preserves Constant Absolute Values of Charges

In a pure U(1)U(1) gauge theory with nn fermions, let S=(S0,S1,…,Sn−1)∈QnS = (S_0, S_1, \dots, S_{n-1}) \in \mathbb{Q}^n be a charge configuration. If all charges in SS have the same absolute value, such that ∣Si∣=∣Sj∣|S_i| = |S_j| for all i,j∈{0,1,…,n−1}i, j \in \{0, 1, \dots, n-1\}, then the configuration obtained by sorting SS also satisfies the condition that all its components have the same absolute value.

definition

Sorted charge assignment with constant absolute value ∣Si∣|S_i|

For a charge assignment S=(S1,S2,…,Sn)∈QnS = (S_1, S_2, \dots, S_n) \in \mathbb{Q}^n within a pure U(1)U(1) gauge theory with nn fermions, the property `ConstAbsSorted` is satisfied if the charges are sorted in non-decreasing order, S1≤S2≤⋯≤SnS_1 \le S_2 \le \dots \le S_n, and all charges have the same absolute value, such that ∣Si∣=∣Sj∣|S_i| = |S_j| for all i,j∈{1,…,n}i, j \in \{1, \dots, n\}.

theorem

Si=SkS_i = S_k for i≤ki \le k and Sk≤0S_k \le 0 in sorted constant absolute value assignments

Let S=(S0,S1,…,Sn)S = (S_0, S_1, \dots, S_n) be a charge assignment for a pure U(1)U(1) gauge theory with n+1n+1 fermions such that the charges are sorted in non-decreasing order (S0≤S1≤⋯≤SnS_0 \le S_1 \le \dots \le S_n) and all charges have the same absolute value (∣Si∣=∣Sj∣|S_i| = |S_j| for all i,ji, j). For any indices i,k∈{0,1,…,n}i, k \in \{0, 1, \dots, n\}, if i≤ki \le k and the charge SkS_k is non-positive (Sk≤0S_k \le 0), then Si=SkS_i = S_k.

theorem

Si≤0  ⟹  Si=S0S_i \le 0 \implies S_i = S_0 in sorted constant absolute value assignments

Let S=(S0,S1,…,Sn)S = (S_0, S_1, \dots, S_n) be a charge assignment for a pure U(1)U(1) gauge theory with n+1n+1 fermions such that the charges are sorted in non-decreasing order (S0≤S1≤⋯≤SnS_0 \le S_1 \le \dots \le S_n) and all charges have the same absolute value (∣Si∣=∣Sj∣|S_i| = |S_j| for all i,j∈{0,1,…,n}i, j \in \{0, 1, \dots, n\}). If for some index ii, the charge SiS_i is non-positive (Si≤0S_i \le 0), then SiS_i must be equal to the first charge S0S_0.

theorem

If 0≤Sk0 \le S_k and k≤ik \le i, then Si=SkS_i = S_k for sorted constant absolute value charges

Consider a pure U(1)U(1) gauge theory with n+1n+1 fermions and a charge assignment S=(S0,S1,…,Sn)∈Qn+1S = (S_0, S_1, \dots, S_n) \in \mathbb{Q}^{n+1}. Suppose the charges are sorted in non-decreasing order (S0≤S1≤⋯≤SnS_0 \le S_1 \le \dots \le S_n) and all charges have the same absolute value (∣Si∣=∣Sj∣|S_i| = |S_j| for all indices i,ji, j). If for some index kk, the charge SkS_k is non-negative (0≤Sk0 \le S_k), then for any index ii such that k≤ik \le i, it holds that Si=SkS_i = S_k.

theorem

0≤S0  ⟹  Si=S00 \le S_0 \implies S_i = S_0 for sorted charges with constant absolute value

Let S=(S0,S1,…,Sn)∈Qn+1S = (S_0, S_1, \dots, S_n) \in \mathbb{Q}^{n+1} be a charge assignment for a pure U(1)U(1) gauge theory with n+1n+1 fermions. Suppose the charges are sorted in non-decreasing order (S0≤S1≤⋯≤SnS_0 \le S_1 \le \dots \le S_n) and all charges have the same absolute value (∣Si∣=∣Sj∣|S_i| = |S_j| for all i,j∈{0,…,n}i, j \in \{0, \dots, n\}). If the first charge is non-negative (0≤S00 \le S_0), then for any index i∈{0,…,n}i \in \{0, \dots, n\}, it holds that Si=S0S_i = S_0.

theorem

Si≤0S_i \le 0 and Sj≥0S_j \ge 0 implies Si=−SjS_i = -S_j for constant absolute charges

Let S=(S0,S1,…,Sn)∈Qn+1S = (S_0, S_1, \dots, S_n) \in \mathbb{Q}^{n+1} be a charge assignment for a pure U(1)U(1) gauge theory with n+1n+1 fermions that is sorted (S0≤S1≤⋯≤SnS_0 \le S_1 \le \dots \le S_n) and where all charges have the same absolute value (∣Si∣=∣Sj∣|S_i| = |S_j| for all i,ji, j). For any indices i,j∈{0,1,…,n}i, j \in \{0, 1, \dots, n\}, if Si≤0S_i \le 0 and Sj≥0S_j \ge 0, then Si=−SjS_i = -S_j.

theorem

If S0=0S_0 = 0 for a sorted constant-absolute-value charge assignment, then S=0S = 0

Let S=(S0,S1,…,Sn)S = (S_0, S_1, \dots, S_n) be a vector of rational charges for a pure U(1)U(1) gauge theory with n+1n+1 fermions. Suppose that SS satisfies the condition that its charges are sorted in non-decreasing order (S0≤S1≤⋯≤SnS_0 \le S_1 \le \dots \le S_n) and all charges have the same absolute value (∣Si∣=∣Sj∣|S_i| = |S_j| for all i,ji, j). If the first charge is zero (S0=0S_0 = 0), then all charges in the vector are zero (S=0S = 0).

definition

Boundary at index kk defined by Sk<0<Sk+1S_k < 0 < S_{k+1}

Let S=(S0,S1,…,Sn)∈Qn+1S = (S_0, S_1, \dots, S_n) \in \mathbb{Q}^{n+1} be a vector of charges for an anomaly cancellation system (ACC) of a pure U(1)U(1) gauge theory with n+1n+1 fermions. For an index k∈{0,1,…,n−1}k \in \{0, 1, \dots, n-1\}, kk is defined as a **boundary** if the kk-th charge is strictly negative (Sk<0S_k < 0) and the (k+1)(k+1)-th charge is strictly positive (Sk+1>0S_{k+1} > 0).

theorem

Sk=S0S_k = S_0 for a boundary index kk in sorted constant-absolute-value assignments

Let S=(S0,S1,…,Sn)S = (S_0, S_1, \dots, S_n) be a charge assignment for a pure U(1)U(1) gauge theory with n+1n+1 fermions, such that the charges are sorted in non-decreasing order (S0≤S1≤⋯≤SnS_0 \le S_1 \le \dots \le S_n) and all charges have the same absolute value (∣Si∣=∣Sj∣|S_i| = |S_j| for all i,j∈{0,…,n}i, j \in \{0, \dots, n\}). If an index k∈{0,…,n−1}k \in \{0, \dots, n-1\} is a boundary, defined by the condition Sk<0<Sk+1S_k < 0 < S_{k+1}, then the kk-th charge is equal to the first charge (Sk=S0S_k = S_0).

theorem

Sk+1=−S0S_{k+1} = -S_0 for a boundary index kk in sorted constant-absolute-value assignments

Let S=(S0,S1,…,Sn)∈Qn+1S = (S_0, S_1, \dots, S_n) \in \mathbb{Q}^{n+1} be a charge assignment for a pure U(1)U(1) gauge theory with n+1n+1 fermions, such that the charges are sorted in non-decreasing order (S0≤S1≤⋯≤SnS_0 \le S_1 \le \dots \le S_n) and all charges have the same absolute value (∣Si∣=∣Sj∣|S_i| = |S_j| for all i,j∈{0,…,n}i, j \in \{0, \dots, n\}). If an index k∈{0,…,n−1}k \in \{0, \dots, n-1\} is a boundary, defined by the condition Sk<0<Sk+1S_k < 0 < S_{k+1}, then the (k+1)(k+1)-th charge is the negative of the first charge, Sk+1=−S0S_{k+1} = -S_0.

theorem

(k+1)+(n+1−(k+1))=n+1(k+1) + (n+1 - (k+1)) = n+1

For any natural number nn and any index k∈{0,…,n−1}k \in \{0, \dots, n-1\}, the sum of the numerical value of the successor of kk (denoted k+1k+1) and the difference between the total number of elements n+1n+1 and k+1k+1 is equal to n+1n+1.

theorem

Gravitational Anomaly Sum over Partitioned Index Range

For a pure U(1)U(1) gauge theory with n+1n+1 Weyl fermions and a charge vector S∈Qn+1S \in \mathbb{Q}^{n+1}, the gravitational anomaly, defined as the sum of all charges ∑Si\sum S_i, is equal to the sum of the charges SiS_i where the index ii ranges over a set of size (k+1)+(n+1−(k+1))(k+1) + (n+1 - (k+1)) for any k∈{0,…,n−1}k \in \{0, \dots, n-1\}.

theorem

∑Si=(2k+1−n)S0\sum S_i = (2k + 1 - n) S_0 for constant absolute value charges with boundary kk

Let S=(S0,S1,…,Sn)∈Qn+1S = (S_0, S_1, \dots, S_n) \in \mathbb{Q}^{n+1} be a charge assignment for a pure U(1)U(1) gauge theory with n+1n+1 fermions. Suppose the charges are sorted in non-decreasing order (S0≤S1≤⋯≤SnS_0 \leq S_1 \leq \dots \leq S_n) and all charges have the same absolute value (∣Si∣=∣Sj∣|S_i| = |S_j| for all i,ji, j). If an index k∈{0,…,n−1}k \in \{0, \dots, n-1\} is a boundary, defined by Sk<0<Sk+1S_k < 0 < S_{k+1}, then the gravitational anomaly (the sum of the charges) is given by: ∑i=0nSi=(2k+1−n)S0\sum_{i=0}^n S_i = (2k + 1 - n) S_0 where kk is the index of the last negative charge and S0S_0 is the value of the first charge.

definition

The charge vector SS has a boundary ∃k,Sk<0<Sk+1\exists k, S_k < 0 < S_{k+1}

Let S=(S0,S1,…,Sn)∈Qn+1S = (S_0, S_1, \dots, S_n) \in \mathbb{Q}^{n+1} be a vector of charges for a pure U(1)U(1) gauge theory with n+1n+1 fermions. The charge vector SS is said to **have a boundary** if there exists an index k∈{0,1,…,n−1}k \in \{0, 1, \dots, n-1\} that satisfies the boundary condition, namely that Sk<0S_k < 0 and Sk+1>0S_{k+1} > 0.

theorem

¬HasBoundary S∧S0<0  ⟹  Si=S0\neg \text{HasBoundary } S \wedge S_0 < 0 \implies S_i = S_0 for sorted constant absolute charges

Let S=(S0,S1,…,Sn)∈Qn+1S = (S_0, S_1, \dots, S_n) \in \mathbb{Q}^{n+1} be a charge assignment for a pure U(1)U(1) gauge theory with n+1n+1 fermions such that the charges are sorted in non-decreasing order (S0≤S1≤⋯≤SnS_0 \le S_1 \le \dots \le S_n) and all charges have the same absolute value (∣Si∣=∣Sj∣|S_i| = |S_j| for all i,j∈{0,1,…,n}i, j \in \{0, 1, \dots, n\}). If the charge vector SS does not have a boundary (meaning there is no index kk such that Sk<0<Sk+1S_k < 0 < S_{k+1}) and the first charge is negative (S0<0S_0 < 0), then all charges in the vector are equal to the first charge, i.e., Si=S0S_i = S_0 for all i∈{0,1,…,n}i \in \{0, 1, \dots, n\}.

theorem

¬HasBoundary S  ⟹  Si=S0\neg \text{HasBoundary } S \implies S_i = S_0 for sorted charges with constant absolute value

Let S=(S0,S1,…,Sn)∈Qn+1S = (S_0, S_1, \dots, S_n) \in \mathbb{Q}^{n+1} be a charge assignment for a pure U(1)U(1) gauge theory with n+1n+1 fermions. Suppose the charges are sorted in non-decreasing order (S0≤S1≤⋯≤SnS_0 \le S_1 \le \dots \le S_n) and all charges have the same absolute value (∣Si∣=∣Sj∣|S_i| = |S_j| for all i,j∈{0,…,n}i, j \in \{0, \dots, n\}). If the charge vector SS does not have a boundary (meaning there is no index kk such that Sk<0<Sk+1S_k < 0 < S_{k+1}), then all charges in the vector are equal to the first charge, i.e., Si=S0S_i = S_0 for all i∈{0,1,…,n}i \in \{0, 1, \dots, n\}.

theorem

Gravitational Anomaly ∑Si=(n+1)S0\sum S_i = (n+1) S_0 for Constant-Absolute-Value Charges without Boundary

Let S=(S0,S1,…,Sn)∈Qn+1S = (S_0, S_1, \dots, S_n) \in \mathbb{Q}^{n+1} be a charge assignment for a pure U(1)U(1) gauge theory with n+1n+1 fermions such that the charges are sorted in non-decreasing order (S0≤S1≤⋯≤SnS_0 \le S_1 \le \dots \le S_n) and all charges have the same absolute value (∣Si∣=∣Sj∣|S_i| = |S_j| for all i,j∈{0,…,n}i, j \in \{0, \dots, n\}). If the charge vector SS does not have a boundary (meaning there is no index kk such that Sk<0<Sk+1S_k < 0 < S_{k+1}), then the gravitational anomaly, defined as the sum of the charges ∑i=0nSi\sum_{i=0}^n S_i, is equal to (n+1)S0(n+1) S_0.

theorem

A0≠0  ⟹  HasBoundaryA_0 \neq 0 \implies \text{HasBoundary} for sorted linear solutions with constant absolute value

Consider a pure U(1)U(1) gauge theory with n+1n+1 fermions. Let A=(A0,A1,…,An)∈Qn+1A = (A_0, A_1, \dots, A_n) \in \mathbb{Q}^{n+1} be a vector of rational charges that satisfies the linear anomaly cancellation condition ∑i=0nAi=0\sum_{i=0}^n A_i = 0. Suppose the charges are sorted in non-decreasing order (A0≤A1≤⋯≤AnA_0 \le A_1 \le \dots \le A_n) and all charges have the same absolute value (∣Ai∣=∣Aj∣|A_i| = |A_j| for all i,j∈{0,…,n}i, j \in \{0, \dots, n\}). If the first charge is non-zero (A0≠0A_0 \neq 0), then the charge vector AA has a boundary, meaning there exists an index k∈{0,…,n−1}k \in \{0, \dots, n-1\} such that Ak<0A_k < 0 and Ak+1>0A_{k+1} > 0.

theorem

Non-zero constant absolute value linear solutions for 2n+12n+1 fermions have no boundary

Consider a pure U(1)U(1) gauge theory with an odd number of fermions 2n+12n + 1. Let A=(A0,A1,…,A2n)∈Q2n+1A = (A_0, A_1, \dots, A_{2n}) \in \mathbb{Q}^{2n+1} be a charge assignment that satisfies the linear anomaly cancellation condition ∑i=02nAi=0\sum_{i=0}^{2n} A_i = 0. Suppose the charges are sorted such that A0≤A1≤⋯≤A2nA_0 \le A_1 \le \dots \le A_{2n} and all charges have the same absolute value ∣Ai∣=∣Aj∣|A_i| = |A_j| for all i,ji, j. If the first charge is non-zero (A0≠0A_0 \neq 0), then the charge vector AA has no boundary, meaning there is no index k∈{0,…,2n−1}k \in \{0, \dots, 2n-1\} such that Ak<0<Ak+1A_k < 0 < A_{k+1}.

theorem

A0=0A_0 = 0 for sorted constant-absolute-value linear solutions with 2n+12n+1 fermions

Consider a pure U(1)U(1) gauge theory with an odd number of fermions 2n+12n + 1. Let A=(A0,A1,…,A2n)∈Q2n+1A = (A_0, A_1, \dots, A_{2n}) \in \mathbb{Q}^{2n+1} be a vector of rational charges that satisfies the linear anomaly cancellation condition ∑i=02nAi=0\sum_{i=0}^{2n} A_i = 0. Suppose the charges are sorted in non-decreasing order (A0≤A1≤⋯≤A2nA_0 \le A_1 \le \dots \le A_{2n}) and all charges have the same absolute value (∣Ai∣=∣Aj∣|A_i| = |A_j| for all i,j∈{0,…,2n}i, j \in \{0, \dots, 2n\}). Then the first charge A0A_0 must be equal to zero.

theorem

A=0A = 0 for sorted constant-absolute-value linear solutions with an odd number of fermions

Consider a pure U(1)U(1) gauge theory with an odd number of fermions 2n+12n + 1. Let A=(A0,A1,…,A2n)∈Q2n+1A = (A_0, A_1, \dots, A_{2n}) \in \mathbb{Q}^{2n+1} be a charge assignment that satisfies the linear anomaly cancellation condition ∑i=02nAi=0\sum_{i=0}^{2n} A_i = 0. If the charges are sorted in non-decreasing order (A0≤A1≤⋯≤A2nA_0 \le A_1 \le \dots \le A_{2n}) and all charges have the same absolute value (∣Ai∣=∣Aj∣|A_i| = |A_j| for all i,ji, j), then AA must be the zero vector, i.e., A=0A = 0.

theorem

Boundary index k=nk=n for constant absolute value linear solutions with 2n+22n+2 fermions

Consider a pure U(1)U(1) gauge theory with 2n+22n+2 fermions having rational charges x=(x0,x1,…,x2n+1)x = (x_0, x_1, \dots, x_{2n+1}). Suppose the charges satisfy the linear anomaly cancellation condition ∑i=02n+1xi=0\sum_{i=0}^{2n+1} x_i = 0, are non-zero (x0≠0x_0 \neq 0), and are sorted such that they all have the same absolute value (x0≤x1≤⋯≤x2n+1x_0 \le x_1 \le \dots \le x_{2n+1} and ∣xi∣=∣xj∣|x_i| = |x_j| for all i,ji, j). If an index k∈{0,…,2n}k \in \{0, \dots, 2n\} is a boundary such that xk<0<xk+1x_k < 0 < x_{k+1}, then k=nk = n.

theorem

xi=x0x_i = x_0 for i≤ni \le n in sorted constant-absolute-value linear solutions for 2n+22n+2 fermions

Consider a pure U(1)U(1) gauge theory with 2n+22n+2 fermions. Let x=(x0,x1,…,x2n+1)x = (x_0, x_1, \dots, x_{2n+1}) be a vector of rational charges that satisfies the linear anomaly cancellation condition ∑j=02n+1xj=0\sum_{j=0}^{2n+1} x_j = 0. Suppose the charges are sorted in non-decreasing order (x0≤x1≤⋯≤x2n+1x_0 \le x_1 \le \dots \le x_{2n+1}) and all have the same absolute value (∣xi∣=∣xj∣|x_i| = |x_j| for all i,j∈{0,…,2n+1}i, j \in \{0, \dots, 2n+1\}). If the first charge is non-zero (x0≠0x_0 \neq 0), then for any index i∈{0,1,…,n}i \in \{0, 1, \dots, n\}, the ii-th charge is equal to the first charge (xi=x0x_i = x_0).

theorem

xi=x0x_i = x_0 for i≤ni \le n in sorted constant-absolute-value linear solutions for 2n+22n+2 fermions

Consider a pure U(1)U(1) gauge theory with 2n+22n+2 fermions. Let x=(x0,x1,…,x2n+1)x = (x_0, x_1, \dots, x_{2n+1}) be a vector of rational charges that satisfies the linear anomaly cancellation condition ∑j=02n+1xj=0\sum_{j=0}^{2n+1} x_j = 0. Suppose the charges are sorted in non-decreasing order (x0≤x1≤⋯≤x2n+1x_0 \le x_1 \le \dots \le x_{2n+1}) and all have the same absolute value (∣xj∣=∣xk∣|x_j| = |x_k| for all j,k∈{0,…,2n+1}j, k \in \{0, \dots, 2n+1\}). Then for any index i∈{0,1,…,n}i \in \{0, 1, \dots, n\}, the ii-th charge is equal to the first charge, xi=x0x_i = x_0.

theorem

xn+1+i=−x0x_{n+1+i} = -x_0 for sorted constant-absolute-value linear solutions with 2n+22n+2 fermions

Consider a pure U(1)U(1) gauge theory with 2n+22n+2 fermions having rational charges x=(x0,x1,…,x2n+1)x = (x_0, x_1, \dots, x_{2n+1}). Suppose the charges satisfy the linear anomaly cancellation condition ∑j=02n+1xj=0\sum_{j=0}^{2n+1} x_j = 0, are non-zero (x0≠0x_0 \neq 0), and are sorted such that they all have the same absolute value (x0≤x1≤⋯≤x2n+1x_0 \le x_1 \le \dots \le x_{2n+1} and ∣xj∣=∣xk∣|x_j| = |x_k| for all j,k∈{0,…,2n+1}j, k \in \{0, \dots, 2n+1\}). Then for any index i∈{0,1,…,n}i \in \{0, 1, \dots, n\}, the charge at index n+1+in+1+i is equal to the negative of the first charge, xn+1+i=−x0x_{n+1+i} = -x_0.

theorem

xn+1+i=−x0x_{n+1+i} = -x_0 for sorted constant-absolute-value linear solutions with 2n+22n+2 fermions

Consider a pure U(1)U(1) gauge theory with 2n+22n+2 fermions and rational charges x=(x0,x1,…,x2n+1)x = (x_0, x_1, \dots, x_{2n+1}). If the charges satisfy the linear anomaly cancellation condition ∑j=02n+1xj=0\sum_{j=0}^{2n+1} x_j = 0, are sorted in non-decreasing order (x0≤x1≤⋯≤x2n+1x_0 \le x_1 \le \dots \le x_{2n+1}), and all have the same absolute value (∣xj∣=∣xk∣|x_j| = |x_k| for all j,kj, k), then for any index i∈{0,1,…,n}i \in \{0, 1, \dots, n\}, the charge at index n+1+in+1+i is equal to the negative of the first charge, xn+1+i=−x0x_{n+1+i} = -x_0.

theorem

Linear solutions with constant absolute value for 2n+12n+1 fermions are zero (S=0S=0)

Consider a pure U(1)U(1) gauge theory with an odd number of fermions 2n+12n + 1. Let S=(S0,S1,…,S2n)∈Q2n+1S = (S_0, S_1, \dots, S_{2n}) \in \mathbb{Q}^{2n+1} be a charge assignment that satisfies the linear anomaly cancellation condition ∑i=02nSi=0\sum_{i=0}^{2n} S_i = 0. If all charges in SS have the same absolute value, such that ∣Si∣=∣Sj∣|S_i| = |S_j| for all i,j∈{0,1,…,2n}i, j \in \{0, 1, \dots, 2n\}, then SS must be the zero vector, i.e., S=0S = 0.

theorem

Linear Solutions with Constant Absolute Charges for 2n+22n+2 Fermions are Vector-like

Consider a pure U(1)U(1) gauge theory with an even number of fermions 2n+22n + 2 (where n∈Nn \in \mathbb{N}). Let S=(x0,x1,…,x2n+1)S = (x_0, x_1, \dots, x_{2n+1}) be a vector of rational charges that satisfies the linear anomaly cancellation condition ∑i=02n+1xi=0\sum_{i=0}^{2n+1} x_i = 0. If all charges in SS have the same absolute value, ∣xi∣=∣xj∣|x_i| = |x_j| for all i,ji, j, then the charge assignment SS is vector-like. That is, if the charges are sorted in non-decreasing order x0′≤x1′≤⋯≤x2n+1′x'_0 \le x'_1 \le \dots \le x'_{2n+1}, they satisfy xi′=−xn+1+i′x'_i = -x'_{n+1+i} for all i∈{0,1,…,n}i \in \{0, 1, \dots, n\}.