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The Number π and a Summation by SL(2 , Z). / Kalinin, Nikita; Shkolnikov, Mikhail.
In: Arnold Mathematical Journal, Vol. 3, No. 4, 01.12.2017, p. 511-517.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - The Number π and a Summation by SL(2 , Z)
AU - Kalinin, Nikita
AU - Shkolnikov, Mikhail
PY - 2017/12/1
Y1 - 2017/12/1
N2 - The sum (resp. the sum of squares) of the defects in the triangle inequalities for the area one lattice parallelograms in the first quadrant has a surprisingly simple expression. Namely, let f(a,b,c,d)=a2+b2+c2+d2-(a+c)2+(b+d)2. Then, [Figure not available: see fulltext.][Figure not available: see fulltext.] where the sum runs by all a, b, c, d∈ Z≥ 0 such that ad- bc= 1. We present a proof of these formulae and list several directions for the future studies.
AB - The sum (resp. the sum of squares) of the defects in the triangle inequalities for the area one lattice parallelograms in the first quadrant has a surprisingly simple expression. Namely, let f(a,b,c,d)=a2+b2+c2+d2-(a+c)2+(b+d)2. Then, [Figure not available: see fulltext.][Figure not available: see fulltext.] where the sum runs by all a, b, c, d∈ Z≥ 0 such that ad- bc= 1. We present a proof of these formulae and list several directions for the future studies.
KW - Lattice geometry
KW - pi
KW - Special linear group
KW - Summation
KW - Tropical geometry
UR - http://www.scopus.com/inward/record.url?scp=85033669876&partnerID=8YFLogxK
U2 - 10.1007/s40598-017-0075-9
DO - 10.1007/s40598-017-0075-9
M3 - Article
AN - SCOPUS:85033669876
VL - 3
SP - 511
EP - 517
JO - Arnold Mathematical Journal
JF - Arnold Mathematical Journal
SN - 2199-6792
IS - 4
ER -
ID: 49793573