25,772 research outputs found
Author Peter FitzSimons speaking at the National Library of Australia, Canberra, 13 November 2012 /
No full textTitle from acquisitions documentation.; Part of the collection: Portraits of author Peter FitzSimons speaking at the National Library of Australia, Canberra, 13 November 2012.; Acquired in digital format; access copy available online.; Mode of access: Online.; Photographed by a staff member of the National Library of Australia
The Turán problem for projective geometries
No full textWe consider the following Turán problem. How many edges can there be in a (q + 1)-uniform hypergraph on n vertices that does not contain a copy of the projective geometry PGm(q)? The case q = m = 2 (the Fano plane) was recently solved independently and simultaneously by Keevash and Sudakov (The Turán number of the Fano plane, Combinatorica, to appear) and Füredi and Simonovits (Triple systems not containing a Fano configuration, Combin. Probab. Comput., to appear). Here we obtain estimates for general q and m via the de Caen–Füredi method of links combined with the orbit-stabiliser theorem from elementary group theory. In particular, we improve the known upper and lower bounds in the case q = 2, m = 3
The n-queens problem
No full textThe famous n-queens problem asks how many ways there are to place n queens on an n × n chessboard so that no two queens can attack one another. The toroidal n-queens problem asks the same question where the board is considered on the surface of the torus and was first studied by P´olya in 1918. Let Q(n) denote the number of n-queens configurations on the classical board and T(n) the number of toroidal n-queens configurations. P´olya showed that T(n) > 0 if and only if n ≡ 1, 5 mod 6 and much more recently, in 2017, Luria showed that T(n) ≤ ((1 + o(1))ne−3)n and conjectured equality when n ≡ 1, 5 mod 6. Our main result is a proof of this conjecture, prior to which no non-trivial lower bounds were known to hold for all (sufficiently large) n ≡ 1, 5 mod 6. Furthermore, we also show that Q(n) ≥ ((1 + o(1))ne−3)n for all n ∈ N which was independently proved by Luria and Simkin. Our result counts only those configurations with at most 12 queens attacking toroidally. Combined with our main result, this completely settles a conjecture of Rivin, Vardi and Zimmerman regarding both Q(n) and T(n). Our proof combines a random greedy algorithm to count ‘almost’ configurations with a complex absorbing strategy that uses ideas from the recently developed methods of randomised algebraic construction and iterative absorption.
This is joint work with Peter Keevash
Moral Good, the Beatific Vision, and God’s Kingdom Writings by Germain Grisez and Peter Ryan, S.J.. Edited by Peter J. Weigel
No full textFor close to half a century, the work of Germain Grisez has been highly influential, and his writings continue to receive considerable attention from philosophers and theologians of diverse viewpoints. His co-author for this work is the professor and noted moral theologian Fr. Peter Ryan, S.J., currently the executive director of the Secretariat of Doctrine and Canonical Affairs of the United States Conference of Catholic Bishops (USCCB). These two eminent scholars explore fundamental questions about Christian eschatology, moral theory, the purpose of human life, and the promise of human fulfilment. The authors examine Christian teaching on the final destiny of persons, investigating the meaning of God's kingdom, the hope of the beatific vision, and the centrality of moral goodness and divine grace in one's final end. This work is an ideal source for students, scholars, ministers and lay persons interested in basic questions of Christian theology, the philosophy of religion, ethical theory, and Catholic doctrin
Shadows and intersections: Stability and new proofs
No full textAbstractWe give a short new proof of a version of the Kruskal–Katona theorem due to Lovász. Our method can be extended to a stability result, describing the approximate structure of configurations that are close to being extremal, which answers a question of Mubayi. This in turn leads to another combinatorial proof of a stability theorem for intersecting families, which was originally obtained by Friedgut using spectral techniques and then sharpened by Keevash and Mubayi by means of a purely combinatorial result of Frankl. We also give an algebraic perspective on these problems, giving yet another proof of intersection stability that relies on expansion of a certain Cayley graph of the symmetric group, and an algebraic generalisation of Lovász's theorem that answers a question of Frankl and Tokushige
Murder on the mountain: author talk with Peter J. Wosh
No full textAuthor talk by Peter J. Wosh on May 5th, 2022, on his book, "Murder on the Mountain: crime, passion, and punishment in gilded age New Jersey.
Lunchtime Talk with Author and Attorney Peter Godwin
No full textAuthor and attorney Peter Godwin gave a lunchtime talk about the topics discussed in his book, The Fear, which focuses on the human rights situation in Zimbabwe under the rule of Robert Mugabe
An essay about the Francis Paudras Collection on Bud Powell by Peter Pullman
No full textThis is an essay about the Francis Paudras Collection on Bud Powell written by Peter Pullman, a jazz scholar and author of Wail: The Life of Bud Powell (Brooklyn: Bop Changes, 2012).One image file (pdf)This project was supported by a Recordings at Risk grant from the Council on Library and Information Resources (CLIR). The grant program is made possible by funding from The Andrew W. Mellon Foundation
Professor Peter Singer speaking at the National Press Club Canberra, 11 February 2009 [picture] /
No full textTitle devised by cataloguer based on information from acquisitions documentation.; Part of the collection: Humanitarian author Professor Peter Singer at the National Press Club, Canberra, 11 February 2009.; Acquired in digital format; access copy available online.; Mode of access: Internet via World Wide Web.; Photographed by a staff member of the National Library of Australia, 2009
Loose Hamilton cycles in hypergraphs
No full textAbstractWe prove that any k-uniform hypergraph on n vertices with minimum degree at least n2(k−1)+o(n) contains a loose Hamilton cycle. The proof strategy is similar to that used by Kühn and Osthus for the 3-uniform case. Though some additional difficulties arise in the k-uniform case, our argument here is considerably simplified by applying the recent hypergraph blow-up lemma of Keevash
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