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D preserves real-rootedness by Rolle's theorem and p + c p' is real-rooted for every real c by Rolle's theorem applied to e^(x/c) p; Polya--Schur 1914); when the coefficients of phi have one sign, coefficients of one sign stay of one sign; applied to phi(n, .) for each n","lean_route":null,"lean_declarations":["RealRooted.splits_add_C_mul_derivative_all","RealRooted.splits_C_mul_add_derivative","Polynomial.Splits.derivative"],"certificate_hash":"027a9fca2a0d37ff2d92ecbc2e6e27143f5f290ce7de13449f9c21de0709bb67","verification_polytool":"replayed","verification_lean":"not_attempted","claims":[{"claim":"real_rooted","from_index":0,"region":{"upper":{"closed":true,"value":"0"}}}],"premises":[{"position":0,"node_id":"n-6120ac587df8130e","role":"sequence","name":"Triangle read by rows: T(n,k) is the number of ternary words of length n having k runs of consecutive 0's (0<=k<=ceiling(n/2)).","uses":{"claim":"real_rooted","from_index":0,"region":{"upper":{"closed":true,"value":"0"}}},"uses_text":"Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]"}]}],"used_by":[],"used_by_total":0,"links":[],"oeis":[],"bfiles":[],"oeis_texts":[{"oeis_id":"","target":"node","first_row":0,"oeis_offset":0,"reversed":false,"trim_zeros":"none","regular_triangle":false,"rows_shown":10,"polytool_commit":"c48629374597092cc41ef4d6273f37991516f984","triangle_example":"Triangle begins:\n  0:    0;\n  1:    1;\n  2:    5;\n  3:   17,     4;\n  4:   49,    32;\n  5:  129,   156,    12;\n  6:  321,   600,   132;\n  7:  769,  2004,   840,   32;\n  8: 1793,  6096,  4056,  448;\n  9: 4097, 17356, 16500, 3520, 80;\n","recurrence_sentence":"The row polynomials satisfy -(5*n-5-(6*n^2-4*n-2)*x)*P(n,x) = -(9*n+7-(10*n^2+8*n+14)*x-(8*n^2-8*n-16)*x^2)*P(n-1,x) - (1-(2*n-5)*x-(14*n+22)*x^2+(16*n+16)*x^3)*d/dx P(n-1,x) for n >= 2, with P(0,x) = 0, P(1,x) = 1.","mathematica":"P[0, x_] := 0;\nP[1, x_] := 1;\nP[n_, x_] := P[n, x] = Expand[Together[(-(9*n + 7 - (10*n^2 + 8*n + 14)*x - (8*n^2 - 8*n - 16)*x^2)*P[n - 1, x] - (1 - (2*n - 5)*x - (14*n + 22)*x^2 + (16*n + 16)*x^3)*D[P[n - 1, x], x])/(-5*n + 5 + (6*n^2 - 4*n - 2)*x)]];\nTable[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten","pari":"P(N) = {my(v = vector(N + 1)); 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