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DTSTART:20230312T070000
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DTSTART:20221106T060000
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DTSTART;TZID=America/Toronto:20231026T140000
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URL:https://uwaterloo.ca/combinatorics-and-optimization/events/algebraic-an
 d-enumerative-combinatorics-seminar-david-wagner
SUMMARY:Algebraic and Enumerative Combinatorics Seminar - David Wagner
CLASS:PUBLIC
DESCRIPTION:TITLE: Higher-order correlation inequalities for random spannin
 g trees\n\nSPEAKER:\n David Wagner\n\nAFFILIATION:\n University of Waterlo
 o\n\nLOCATION:\n MC 6029\n\nThere will be a pre-seminar presenting relevan
 t background at the\nbeginning graduate level starting at 1:00 pm.\n\nABST
 RACT: The connection between enumerating spanning trees of a graph\nand th
 e theory of (linear) electrical networks goes all the way back\nto Kirchho
 ff's 1847 paper. It is physically sensible that if one\nincreases the cond
 uctance of one wire in an electrical network\, then\nthe overall conductan
 ce of the network can not decrease. This\ncorresponds to the less obvious 
 fact that any two distinct edges are\nnon-positively correlated\, when one
  chooses a random spanning tree.\nCovariance is the 2-point \"Ursell funct
 ion''\, and expectation is the\n1-point Ursell function. For any subset of
  edges there is an\nassociated Ursell function\, and these are related to 
 occupation\nprobabilities by Möbius inversion. I will discuss some situat
 ions in\nwhich the signs of these Ursell functions can be predicted\, yiel
 ding\nhigher-order correlation inequalities for random spanning trees.
DTSTAMP:20260418T204447Z
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