src/HOL/Hyperreal/Log.thy
changeset 15053 405be2b48f5b
parent 14430 5cb24165a2e1
child 15085 5693a977a767
equal deleted inserted replaced
15052:cc562a263609 15053:405be2b48f5b
    12   powr  :: "[real,real] => real"     (infixr "powr" 80)
    12   powr  :: "[real,real] => real"     (infixr "powr" 80)
    13     --{*exponentation with real exponent*}
    13     --{*exponentation with real exponent*}
    14     "x powr a == exp(a * ln x)"
    14     "x powr a == exp(a * ln x)"
    15 
    15 
    16   log :: "[real,real] => real"
    16   log :: "[real,real] => real"
    17     --{*logarithm of @[term x} to base @[term a}*}
    17     --{*logarithm of @{term x} to base @{term a}*}
    18     "log a x == ln x / ln a"
    18     "log a x == ln x / ln a"
    19 
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    21 
    22 lemma powr_one_eq_one [simp]: "1 powr a = 1"
    22 lemma powr_one_eq_one [simp]: "1 powr a = 1"