:: deftheorem Def4 defines qpoly HURWITZ:def 4 :
for L being non empty well-unital doubleLoopStr
for z being Element of L
for k being Nat
for b₄ being Polynomial of L holds
( b₄ = qpoly (k,z) iff ( ( for i being Nat st i < k holds
b₄ . i = (power L) . (z,((k - i) - 1)) ) & ( for i being Nat st i >= k holds
b₄ . i = 0. L ) ) );