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[parent] properties of the exponential (Theorem)

The exponential operation possesses the following properties.

  • Homogeneity. For $x,y\in\reals^+, p\in \reals$ we have $$(xy)^p = x^p y^p$$
  • Exponent additivity. For $x\in\reals^+$ we have $$x^0=1,\quad x^1 = x,\quad x^{p+q} = x^p x^q,\quad (x^p)^q=x^{pq}\qquad p,q\in\reals.$$
  • Monotonicity. For $x,y\in\reals^+$ with $x<y$ and $p\in \reals^+$ we have $$x^p < y^p,\qquad x^{-p} > y^{-p}.$$
  • Continuity. The exponential operation is continuous with respect to its arguments. To be more precise, the following function is continuous: $$P:\reals^+\times\reals\rightarrow \reals,\qquad P(x,y)=x^y.$$
Let us also note that the exponential operation is characterized (in the sense of existence and uniqueness) by the additivity and continuity properties. [Author's note: One can probably get away with substantially less, but I haven't given this enough thought.]




"properties of the exponential" is owned by rmilson.
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proof of properties of the exponential (Proof) by rspuzio
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Cross-references: additivity, function, arguments, continuous, properties, exponential operation
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This is version 12 of properties of the exponential, born on 2002-02-27, modified 2004-09-29.
Object id is 2731, canonical name is PropertiesOfTheExponential.
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AMS MSC26A03 (Real functions :: Functions of one variable :: Foundations: limits and generalizations, elementary topology of the line)

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