Description: Hellinger-Toeplitz Theorem: any self-adjoint linear operator defined on all of Hilbert space is bounded. Theorem 10.1-1 of Kreyszig p. 525. Discovered by E. Hellinger and O. Toeplitz in 1910, "it aroused both admiration and puzzlement since the theorem establishes a relation between properties of two different kinds, namely, the properties of being defined everywhere and being bounded." (Contributed by NM, 11-Jan-2008) (Revised by Mario Carneiro, 23-Aug-2014) (New usage is discouraged.)
Ref | Expression | ||
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Hypotheses | htth.1 | |
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htth.2 | |
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htth.3 | |
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htth.4 | |
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Assertion | htth | |
Step | Hyp | Ref | Expression |
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1 | htth.1 | |
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2 | htth.2 | |
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3 | htth.3 | |
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4 | htth.4 | |
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5 | oveq12 | |
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6 | 5 | anidms | |
7 | 3 6 | eqtrid | |
8 | 7 | eleq2d | |
9 | fveq2 | |
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10 | 1 9 | eqtrid | |
11 | fveq2 | |
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12 | 2 11 | eqtrid | |
13 | 12 | oveqd | |
14 | 12 | oveqd | |
15 | 13 14 | eqeq12d | |
16 | 10 15 | raleqbidv | |
17 | 10 16 | raleqbidv | |
18 | 8 17 | anbi12d | |
19 | oveq12 | |
|
20 | 19 | anidms | |
21 | 4 20 | eqtrid | |
22 | 21 | eleq2d | |
23 | 18 22 | imbi12d | |
24 | eqid | |
|
25 | eqid | |
|
26 | eqid | |
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27 | eqid | |
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28 | eqid | |
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29 | eqid | |
|
30 | 29 | cnchl | |
31 | 30 | elimel | |
32 | simpl | |
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33 | simpr | |
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34 | oveq1 | |
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35 | fveq2 | |
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36 | 35 | oveq1d | |
37 | 34 36 | eqeq12d | |
38 | fveq2 | |
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39 | 38 | oveq2d | |
40 | oveq2 | |
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41 | 39 40 | eqeq12d | |
42 | 37 41 | cbvral2vw | |
43 | 33 42 | sylib | |
44 | oveq1 | |
|
45 | 44 | cbvmptv | |
46 | fveq2 | |
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47 | 46 | oveq2d | |
48 | 47 | mpteq2dv | |
49 | 45 48 | eqtrid | |
50 | 49 | cbvmptv | |
51 | fveq2 | |
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52 | 51 | breq1d | |
53 | 52 | cbvrabv | |
54 | 53 | imaeq2i | |
55 | 24 25 26 27 28 31 29 32 43 50 54 | htthlem | |
56 | 23 55 | dedth | |
57 | 56 | 3impib | |