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Difference between revisions of "Unitarily-equivalent representations"

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Representations <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/u/u095/u095520/u0955201.png" />, <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/u/u095/u095520/u0955202.png" /> of a group (algebra, ring, semi-group, cf. [[Representation of a group|Representation of a group]]) <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/u/u095/u095520/u0955203.png" /> in Hilbert spaces <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/u/u095/u095520/u0955204.png" />, <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/u/u095/u095520/u0955205.png" />, satisfying the condition
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Representations $\pi_1$, $\pi_2$ of a group (algebra, ring, semi-group, cf. [[Representation of a group|Representation of a group]]) $X$ in Hilbert spaces $H_1$, $H_2$, satisfying the condition
  
<table class="eq" style="width:100%;"> <tr><td valign="top" style="width:94%;text-align:center;"><img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/u/u095/u095520/u0955206.png" /></td> </tr></table>
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$$U\pi_1(x)=\pi_2(x)U$$
  
for a certain [[Unitary operator|unitary operator]] <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/u/u095/u095520/u0955207.png" /> and all <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/u/u095/u095520/u0955208.png" />. Cf. [[Intertwining operator|Intertwining operator]].
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for a certain [[Unitary operator|unitary operator]] $U\colon H_1\to H_2$ and all $x\in X$. Cf. [[Intertwining operator|Intertwining operator]].

Latest revision as of 16:52, 16 August 2014

Representations $\pi_1$, $\pi_2$ of a group (algebra, ring, semi-group, cf. Representation of a group) $X$ in Hilbert spaces $H_1$, $H_2$, satisfying the condition

$$U\pi_1(x)=\pi_2(x)U$$

for a certain unitary operator $U\colon H_1\to H_2$ and all $x\in X$. Cf. Intertwining operator.

How to Cite This Entry:
Unitarily-equivalent representations. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Unitarily-equivalent_representations&oldid=18693
This article was adapted from an original article by A.I. Shtern (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article