TY - JOUR TI - On the gradient of quasi-homogeneous polynomials AU - Haraux, Alain AU - Pham, Tien Son TI - On the gradient of quasi-homogeneous polynomials AB - Let K be the real or the complex field, and let f : Kn → K be a quasi-homogeneous polynomial with weight w := (w1;w2;...,wn) and degree d. Assume that rf(0) = 0. Łojasiewicz well known gradient inequality states that there exists an open neighbourhood U of the origin in Kn and two positive constants c and p < 1 such that for any x → U we have rf(x) > cf(x)p: We prove that if the set K - (f) of points where the Fedoryuk condition fails to hold is nite, then the gradient inequality holds true with p = 1-minj wj/d. It is also shown that if n = 2; then K-(f) is either empty or reduced to {0}. VL - 2011 IS - Tom 49 PY - 2012 SN - 0083-4386 C1 - 2084-3828 SP - 45 EP - 57 DO - 10.4467/20843828AM.12.003.0455 UR - https://ejournals.eu/czasopismo/universitatis-iagellonicae-acta-mathematica/artykul/on-the-gradient-of-quasi-homogeneous-polynomials KW - Quasi-homogeneous KW - Lojasiewicz's gradient inequality KW - Lojasiewicz exponent KW - Fedoryuk's condition