1,721,174 research outputs found
Polynomial identities related to special Schubert varieties
No full textLet S be a single condition Schubert variety with an arbitrary number of strata. Recently, an explicit description of the summands involved in the decomposition theorem applied to such a variety has been obtained in a paper of the second author. Starting from this result, we provide an explicit description of the Poincaré polynomial of the intersection cohomology of S by means of the Poincaré polynomials of its strata, obtaining interesting polynomial identities relating Poincaré polynomials of several Grassmannians, both by a local and by a global point of view. We also present a symbolic study of a particular case of these identities
Regularity of primes associated with polynomial parametrisations
No full textWe prove a doubly exponential bound for the Castelnuovo-Mumford
regularity of prime ideals defining varieties with polynomial parametrisation
ANATOMIA CHIRURGICA DEL III VENTRICOLO. A PROPOSITO DELL’APPROCCIO INTERTALAMO-TRIGONALE
No full textDynamics of lagoon ecosystems
No full textThe dynamic behaviour of a lagoon ecosystem is investigated by using an eutrophication model. The phosphorous external load is assumed as control parameter. The response diagram, obtained by simulation, varying the value of control parameter, shows the existence of different ranges of stability of the ecosystem, characterized by the dominance of a specific group of primary produces and by a different ecosystem vulnerability to Summer water anoxia. A catastrophic bifurcation occurs for a critical value of the control parameter, which manifests as an abrupt change of the dominant specie from eelgrass to macroalgae. The serious consequences of such a selection in terms of eutrophication processes, anoxic crisis vulnerability and management policies for ecosystems subject to alternate states are emphasised
Reflections about abortion limitation | [Reflexões sobre a limitação do aborto]
Full text linkO debate sobre o aborto ainda não encontrou uma solução clara. Na verdade, ainda há discussão sobre quais devem ser os limites deste procedimento. Esta incerteza está relacionada com a falta de uma definição clara da vida humana: quando pode o produto da concepção ser definido como um ser humano com plenos direitos médico-legais? Com base na resposta a esta pergunta, os vários governos mundiais elaboraram leis mais ou menos restritivas que regulam o aborto. Desde maio de 2019, alguns Estados americanos têm restringido consideravelmente a possibilidade de realizar o aborto em seu território. Alabama praticamente proibiu o aborto em qualquer circunstância (incluindo incesto e estupro). Obviamente, estas políticas restritivas tiveram um impacto significativo no debate social, bioético e jurídico, a nível mundial, sobre o aborto. Este artigo analisa as implicações dessas políticas com foco nos direitos fundamentais da mulher: o direito à saúde e o direito à autodeterminação.The debate on abortion has not yet found a clear solution. In fact, there is still discus-sion about what the limits of this procedure should be. This uncertainty is related to the lack of a clear definition of human life: when can the product of conception be defined as a human being with full medical-legal rights? Based on the answer to this question, the various world governments have drafted more or less restrictive laws regulating abortion. Since May 2019, some American states have considerably restricted the possibility of car-rying out abortion on their territory. Alabama has practically banned abortion in any circumstance (including incest and rape). Obviously, these restrictive policies have had a significant impact on the social, bioethical and legal debate, concerning abortion, globally. This paper analyses the implications of these policies with a focus on women’s fundamental rights: the right to health and the right to self-determination
Simulazione numerica tridimensionale dei campi di moto indotti dal vento
No full textNell’articolo viene proposto un modello numerico tridimensionale al volume finiti, che viene utilizzato per la simulazione di campi di moto indotti dal mento in corpi idrici con batimetria complessa. I risultati numerici sono confrontati con misure sperimentali. Al fine di verificare gli effetti sul calcolo del campi idrodinamici di alcume ipotesi simplificative, relative alla distribuzione verticale della pressione e degli sforzi di Reynolds, sono stati quindi condotti alcuni test numerici, dai quali si è evidenziato che l’ipotesi di distribuzione idrostatica delle pressioni, cui si fa ricorso nelle approssinazioni di tipo “quasi-3D”, può essere utilizzata per il carcolo del profili verticali della componente di clocità orizaontale ad una certa distanza dalle pereti, ma conduce a risultati poco corrtti in prossimità delle pareti di monte e di valle. Si è inotre verificata l’applicabilità del modello algbrico proposto da Tsanis [23], confrontando il profilo parabolico del coefficiente di viscosità tubolenta assunto da questo mmodello con quello resultante dall’utilizzo del modello K. Tali profili risultano in buon accordo nella maggior parte del dominio considerato, sebbene il modello di Tsanis sobrastimi decisamente le viscosità turbolente in prossimità delle pareti di monte e di valle
Geometric description of lifting monomial ideals
No full textBy focusing our attention on the set of monomials outside a given monomial ideal, we tackle the study of the geometric configurations of (reduced) unions of projective linear varieties arising from lifting monomial ideals via a classic lifting procedure, called t-lifting , and a more general lifting procedure, called pseudo-t-lifting .
We observe that, in contrast to the Artinian case, in the positive dimensional case we may not obtain generalized stick figure also via a generic pseudo-t-lifting .
In particular, in dimension 1 a generic pseudo-1-lifting produces a seminormal union of lines.
Then we give conditions to obtain generalized stick figures by means of pseudo-t-liftings of non-Artinian monomial ideals
The close relation between border and Pommaret marked bases
Full text linkGiven a finite order ideal O in the polynomial ring K[x1, ... , xn] over a field K, let ∂O be the border of O and PO the Pommaret basis of the ideal generated by the terms outside O. In the framework of reduction structures introduced by Ceria, Mora, Roggero in 2019, we investigate relations among ∂O-marked sets (resp. bases) and PO-marked sets (resp. bases). We prove that a ∂O-marked set B is a marked basis if and only if the PO-marked set P contained in B is a marked basis and generates the same ideal as B. Using a functorial description of these marked bases, as a byproduct we obtain that the affine schemes respectively parameterizing ∂O-marked bases and PO-marked bases are isomorphic. We are able to describe this isomorphism as a projection that can be explicitly constructed without the use of Gröbner elimination techniques. In particular, we obtain a straightforward embedding of border schemes in affine spaces of lower dimension. Furthermore, we observe that Pommaret marked schemes give an open covering of Hilbert schemes parameterizing 0-dimensional schemes without any group actions. Several examples are given throughout the paper
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