Konstrukce PRF z axiomů a odvozovacích pravidel
Z ωικι.matfyz.cz
Konstanta C(x)=x
f_1 = o(x) f_2 = I^2_3(x_1, x_2, x_3) f_3 = s(x) f_4 = S^1_3(f_3, f_2) f_5 = R_2(f_1, f_4) f_6 = S^2_1(f_5, I^1_1, I^1_1)
Sčítání
f1 = s(x) f2 = I11(x) f3 = I23(x1, x2, x3) f4 = S13(f1, f3) = λx1x2x3[x2 + 1] f5 = R2(f2, f4) tj. f5(0, x2) = f2(x2) = x2 f5(x1 + 1, x2) = f4(x1, f5(x1, x2), x2) = f5(x1, x2) + 1 sum(x, y) = f5
Násobení
f1 = o(x) f2 = I23 f3 = I33 f4 = S23(sum, f2, f3) f5 = R2(f1, f4) multiply(x, y) = f5
Sign(x)
f1 = o(x) f2 = s(x) f3 = S11(f2, f1) f4 = I33(x1, x2, x3) f5 = S11(f3, f4) f6 = R2(f1, f5) f7 = I11(x1) f8 = S21(f6, f7, f7) sign(x) = f8