interpretation "Rplus" 'plus x y =
(cic:/matita/demo/power_derivative/Rplus.con x y).
-notation "hvbox(a break \middot b)"
- left associative with precedence 55
-for @{ 'times $a $b }.
-
-interpretation "Rmult" 'times x y =
+interpretation "Rmult" 'middot x y =
(cic:/matita/demo/power_derivative/Rmult.con x y).
definition Fplus ≝
interpretation "Fplus" 'plus x y =
(cic:/matita/demo/power_derivative/Fplus.con x y).
-interpretation "Fmult" 'times x y =
+interpretation "Fmult" 'middot x y =
(cic:/matita/demo/power_derivative/Fmult.con x y).
notation "2" with precedence 89
axiom Rplus_Rzero_x: ∀x:R.0+x=x.
axiom Rplus_comm: symmetric ? Rplus.
axiom Rplus_assoc: associative ? Rplus.
-axiom Rmult_Rone_x: ∀x:R.1*x=x.
-axiom Rmult_Rzero_x: ∀x:R.0*x=0.
+axiom Rmult_Rone_x: ∀x:R.1 · x=x.
+axiom Rmult_Rzero_x: ∀x:R.0 · x=0.
axiom Rmult_assoc: associative ? Rmult.
axiom Rmult_comm: symmetric ? Rmult.
axiom Rmult_Rplus_distr: distributive ? Rmult Rplus.
-alias symbol "times" = "Rmult".
+alias symbol "middot" = "Rmult".
alias symbol "plus" = "natural plus".
definition monomio ≝
axiom derivative_x1: D[x] = 1.
axiom derivative_mult: ∀f,g:R→R. D[f·g] = D[f]·g + f·D[g].
-alias symbol "times" = "Fmult".
+alias symbol "middot" = "Fmult".
theorem derivative_power: ∀n:nat. D[x \sup n] = n·x \sup (pred n).
assume n:nat.
case left.
suppose (0 < m) (m_pos).
using (S_pred ? m_pos) we proved (m = 1 + pred m) (H1).
- done.
+ by H1 done.
case right.
suppose (0=m) (m_zero).
- done.
+ by m_zero, Fmult_zero_f done.
conclude
(D[x \sup (1+m)])
= (D[x · x \sup m]).