605 research outputs found
Deformations of special structures in dimensions 6 and 7
No full textIn this thesis, we study three problems in non-Kähler Calabi–Yau geometry and G₂-geometry centered on Reid’s Fantasy [Rei87] and the Hull–Strominger system [Hul86, Str86].
The first concerns the geometrization of conifold transitions, processes which allow us to traverse the moduli space of compact Calabi–Yau threefolds. Work of Fu–Li–Yau [FLY12] and of Collins–Picard–Yau [CPY24] has constructed metrics on both sides of this process which are partial solutions to the Hull–Strominger system. Using these (conformally) balanced and Hermitian Yang–Mills metrics, we show that conifold transitions are continuous in the Gromov–Hausdorff topology.
The next focuses on the Anomaly flow of Phong–Picard–Zhang [PPZ18b]. We extend their ideas from the ′ = 0 case and compute integral Shi-type estimates along the flow for general slope parameter ′. We achieve this by adapting an integration-by-parts type argument instead of the usual Maximum Principle techniques in order to deal with the extra terms that appear. From this, we obtain a smallness condition on ′ that allows the flow to be extended from [0,τ) to a larger interval [0,τ + ϵ).
Finally, we study the relationship between Calabi–Yau geometry and G₂-geometry by considering geometric flows on S¹-fibrations over Calabi–Yau threefolds. In particular, we construct families of closed and coclosed G₂-structures on these fibrations and apply the Laplacian flow and (modified)
coflow respectively. Using these Ans¨atze, we show that on a trivial fibration these flows reduce to particular Monge–Ampère flows on the base manifold. We perform a similar analysis on contact Calabi–Yau 7-folds and obtain conditions for these families to satisfy the flows.Science, Faculty ofMathematics, Department ofGraduat
How to play philosophy: A book for public thinking and the thinking public
No full text"How to Play Philosophy is a series of lyrical, creative essays that explore timeless and timely ideas about who we are and how we live. MIT-trained philosopher Michael Picard shares ideas of numerous. philosophers from conflicting traditions and builds an intellectual background to enable readers to draw their own conclusions." Written in a spirit of free and playful inquiry, the essays were composed originally to support public participatory philosophy, or Café Philosophy, which the author has facilitated for decades. Subjects include Play it With Feeling (Desire, Stress, Anger); Games We Play (Intimacy, Loyalty, Betrayal) and Playing Fair (Values, Good, Integrity), alongside epistemological topics including Truth (Knowledge, Certainty, Objectivity) and the perennial metaphysical quandaries (Human Nature, The Sacred, God). -- Provided by publisher.bookDC Author's celebration 202
Review of the book Philosophy, humor and the human condition: taking ridicule seriously, by L. Amir
No full textDr. Michael Picard (Douglas College) reviews the book Philosophy, Humor and the Human Condition: Taking Ridicule Seriously by Lydia Amir (2019). The book review is in Philosophy of Humor Yearbook, Vol. 2, 2021.Book reviewHumorPhilosophy of humo
Philosophy A to Z: Essays for café philosophy
No full textA collection of essays and other texts of popular philosophy written by best-selling author, Michael Picard, MSc PhD, the MIT-trained philosopher who has facilitated hundreds of Cafe Philosophy dialogues with the public, for which the entries in this accidental lexicon were composed. Intended to stimulate readers' thoughts prior to public participatory philosophy sessions, Picard's writing invites the reader on a tour de force of the philosophical dimensions of contemporary life.
This anti-dictionary explodes the meanings of philosophically-intriguing concepts as it defines and un-defines them. Written by MIT-trained philosopher and author of best-selling This is not a Book (2007), this unique alphabetical collection of provocative essays and other texts tease and treat the reader to fresh and foreign perspectives on dozens of philosophy topics of interest to thinking public and critical seekers anywhere. At times playful or profound, alternately skeptical and reverential, the entries in this philosophical lexicon push paradox and pull for pluralism, spanning the vast range of philosophy, ancient and modern, East and West, social and spiritual, moral and metaphysical, and yet more. This book is for people yearning to explore have fun gaining new perspectives and thinking for themselves, and ready to have their minds ignited by the curious, all-consuming questioning spirit of philosophy. -- From publisher description.bookPublished
Bewusstsein und Realität: die Frage des Idealismus in der frühen indischen Philosophie: [Consciousness and reality: the question of idealism in the early Indian philosophy]
No full textAn audio recording of a lecture by Michael Picard presented before the Gesellschaft für Philosophische Praxis, upon the invitation of Dr. Gerd Achenbach, founder and director of GPP (August 16, 2019).
Delivered in German, it was entitled Bewusstsein und Realität: die Frage des Idealismus in der frühen indischen Philosophie (Consciousness and Reality: the Question of Idealism in the early Indian Philosophy). There were about 40 people in attendance, mostly from the circle of Dr. Achenbach. I owe thanks to Dr. Achenbach and his industrious assistant, Laura V. Adrian, who spent the three days prior to the talk translating my lecture and preparing me to deliver it in German
The construction of Karen Karnak: The multi-author-function
No full textThis thesis is situated within the comparatively recent developments of Web 2.0 and the emergence of interactive WikiMedia, and explores the mode of authorship within a Read/Write culture compared to that of a Read/Only tradition. The hypothesis of this study is that the role of the audience has become merged with the author, and as such, represents new functions and attributes, distinct from a more conventional concept of authorship, in which the roles of audience and author are more separate. Read/Write and participatory culture, as defined by this study, is focused on collaboration, and includes the influences of D.I.Y. culture, Open-Source practices and the production of text by multiple authors. Multi-authorship presents a re-thinking of several concepts which support the notion of the individual author, since the focus of multi-authorship is not on attribution and ownership of a finished text, but on the continued malleability of a text. Modes of multi-authorship, demonstrated in the use of the pseudonyms Alan Smithee and Karen Eliot, represent declarative authors whose names signify multiple origins, whilst concurrently indicating a distinct body of work. The function of these names form an important context to this study, since primary research involves the construction of an experimental mode of multi-authorship utilising WikiMedia technology and the interaction of thirty nine participants, who are invited to create a body of work under the collective pseudonym Karen Karnak. The data generated by this experiment is analysed using aspects of Michel Foucault's author-function to identify and determine power structures inherent in the WikiMedia context. The interplay of power structures, including concepts such as identity, ownership and the body of work, affect the resulting mode of authorship and contribute to the construction of Karen Karnak, suggesting further areas of research into the emerging multi-author
Computer assisted knee replacement surgery : is the movement mainstream?
No full textThe first computer-assisted Total Knee Arthroplasty (TKA) was performed in 1997. The FDA approved computer assisted knee arthroplasty systems used in the early 2000s. Since then, surgeons and institutions all over the world have gradually adopted the technology. While the computer holds an importance place in the majority of workspaces across all industries, computer-assisted surgical technique has yet to become the preferred tool of the orthopaedic surgeon. Why has "e-instrumentation" not yet substituted conventional instrumentation in TKA orthopaedic surgery? In this article, we argue that main reasons which oppose the use of this technology are based on inaccurate or misleading observations. We isolated the factors likely to explain such opposition to this innovation: current results of total knee replacement, surgeon age, operative time, system ergonomics, cost for users, and cost for suppliers and "disruptive" innovations. Other factors such as surgeon habits, hospital environment and available assistance for support, although relevant, are not discussed. We assessed the advantages and drawbacks, costs and benefits of this technology to assess whether or not this opposition is justified. Finally, we explored the reasons why such a technology may impel surgeons to use this technique or any "related technologies" in the future. The main factors limiting TKA navigation spreading amongst orthopaedic surgeons are ergonomics and economics. Other factors, such as current TKA outcomes and surgeon's age are fallacious arguments in the rebuttal of CAS system use. Computer assisted knee arthroplasty surgery is not yet mainstream, but TKA will not escape technological progress
Towards the construction of the heterotic moduli
No full textWe study the moduli space of the heterotic system, which holds significant importance in physics. Fixing the complex structure, we explore the moduli space by considering two different yet “dual” deformation paths starting from a Kähler solution. They correspond to deformations along the Bott-Chern cohomology class and the Aeppli cohomology class respectively. Together with the deformation of the gauge bundle, we prove the existence of heterotic solutions along these two paths using the implicit function theorem. Hence, we construct local coordinates in the neighborhood of a Kähler solution along the submanifold of fixed complex structure on the full heterotic moduli. This is an initial step in constructing the full metric of heterotic moduli.Science, Faculty ofMathematics, Department ofGraduat
An inverse Jacobian algorithm for Picard curves
No full textInternational audienceWe study the inverse Jacobian problem for the case of Picard curves over C. More precisely, we elaborate on an algorithm that, given a small period matrix Ω∈ C3 × 3 corresponding to a principally polarized abelian threefold equipped with an automorphism of order 3, returns a Legendre–Rosenhain equation for a Picard curve with Jacobian isomorphic to the given abelian variety. Our method corrects a formula obtained by Koike–Weng (Math Comput 74(249):499–518, 2005) which is based on a theorem of Siegel. As a result, we apply the algorithm to obtain equations of all the isomorphism classes of Picard curves with maximal complex multiplication by the maximal order of the sextic CM-fields with class number at most 4. In particular, we obtain the complete list of maximal CM Picard curves defined over Q. In the appendix, Vincent gives a correction to the generalization of Takase’s formula for the inverse Jacobian problem for hyperelliptic curves given in [Balakrishnan–Ionica–Lauter–Vincent, LMS J. Comput. Math., 19(suppl. A):283-300, 2016]. © 2021, The Author(s)
On a discrepancy among Picard-Vessiot theories in positive characteristics
No full textThere is a serious discrepancy among literature on the Picard-Vessiot theory in positive characteristics (for iterative differential fields). We consider descriptions of Galois correspondence in four approaches to this subject: Okugawa's result We should use affine group schemes instead of algebraic matrix groups to obtain a suitable Galois correspondence, as in Takeuchi's approach. But intermediate fields are not necessarily fixed fields there. In the second section, we give some sufficient conditions for intermediate artinian simple module algebras to be fixed algebras in the context of the unified Picard-Vessiot theory developed by the author and Masuok
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