# Talk:Lacunary sequence

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Post $\TeX$ notes

• I replace the sequence notation $\{\cdot\}$ by the more usual $(\cdot)$, uncomment the \newcommand for \seq at the start of the file to revert this
• I'm not entirely sure about the MSC here, could someone check it?

--Jjg 22:04, 3 May 2012 (CEST)

About MSC: problematic indeed; but I believe that 42A55 "Lacunary series of trigonometric and other functions; Riesz products" is naturally the secondary classification, since it gives the main motivation here.
And maybe 11B05 "Density, gaps, topology" rather than just 11Bxx? Indeed, lacunary sequences are somehow of very small density, with many large gaps. --Boris Tsirelson 22:31, 3 May 2012 (CEST)
Agreed, thanks Boris --Jjg 23:41, 3 May 2012 (CEST)
Shouldn't the notation $\lfloor\cdot\rfloor$ be used for the integer part? Or $\lceil\cdot\rceil$ (I never remember)? -- Sergei Yakovenko 07:16, 4 May 2012 (CEST)
Convention seems to differ between $\lfloor\cdot\rfloor$ and $[\cdot]$ -- the former is favoured by combinatorics, the latter by number theory and analysis. TBloom 07:43, 4 May 2012 (CEST)
As I remember, $\lfloor\cdot\rfloor$ rounds down $\lceil\cdot\rceil$ rounds up, and $[\cdot]$ rounds towards zero, so $\lfloor\cdot\rfloor$ and $[\cdot]$ are the same for positive numbers --Jjg 10:40, 4 May 2012 (CEST)
Definition style changed according to Talk:EoM:This_project#Style_of_title_and_definition. --Ulf Rehmann 10:28, 4 May 2012 (CEST)
But "A lacunary ..." rather that "The lacunary ...", surely? --Jjg 10:40, 4 May 2012 (CEST)
How to Cite This Entry:
Lacunary sequence. Encyclopedia of Mathematics. URL: http://www.encyclopediaofmath.org/index.php?title=Lacunary_sequence&oldid=25924