let n be Nat; :: thesis: for K being Field
for M1, M2, M3 being Matrix of n,K holds Trace ((M1 + M2) + M3) = ((Trace M1) + (Trace M2)) + (Trace M3)
let K be Field; :: thesis: for M1, M2, M3 being Matrix of n,K holds Trace ((M1 + M2) + M3) = ((Trace M1) + (Trace M2)) + (Trace M3)
let M1, M2, M3 be Matrix of n,K; :: thesis: Trace ((M1 + M2) + M3) = ((Trace M1) + (Trace M2)) + (Trace M3)
Trace ((M1 + M2) + M3) = (Trace (M1 + M2)) + (Trace M3) by Th53;
hence Trace ((M1 + M2) + M3) = ((Trace M1) + (Trace M2)) + (Trace M3) by Th53; :: thesis: verum