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We introduce a novel model that interprets the parallel operator, also present in algebraic calculi, within the context of propositional logic. This interpretation uses the category $\mathbf{Mag}_{\mathbf{Set}}$, whose objects are magmas and whose arrows are functions from the category $\mathbf{Set}$, specifically for the case of the parallel lambda calculus. Similarly, we use the category $\mathbf{AMag}^{\mathcal S}_{\mathbf{Set}}$, whose objects are action magmas and whose arrows are also functions from the category $\mathbf{Set}$, for the case of the algebraic lambda calculus. Our approach diverges from conventional interpretations where disjunctions are handled by coproducts, instead proposing to handle them with the union of disjoint union and the Cartesian product., Comment: 18 pages plus appendix

This paper is dedicated to the memory of Paul Felenbok (1936-2020) who was astronomer at Paris-Meudon observatory, and founded in 1974, fifty years ago, a high altitude station (2930 m), above Saint V{\'e}ran village in the southern Alps (Queyras). It was initially devoted to the study of the solar corona. Following solar eclipses (1970, 1973) observed with the Lallemand electronic camera, the main goal was to detect with this sensitive detector the structures of the far and hot corona in forbidden lines, using either narrow bandpass filters or spectroscopy. But everything had to be done prior to observations: a track, a house for astronomers, a dome and a complex instrument. We summarize here this fantastic adventure, which was partly successful in terms of scientific results and had to stop in 1982; however, the activity of the station resumed after 1989 under the auspices of the ``AstroQueyras'' association, which replaced the coronagraph by a 62 cm night telescope from Haute Provence observatory; the station extended later with two 50 cm telescopes, was rebuilt in 2015 and received the visit of thousands of amateurs.

We present in this paper a compilation of solar atlases from $\lambda$ 3000 {\AA} to $\lambda$ 8800 {\AA} with spectral lines identified by the Moore table and with the corresponding equivalent Lande factors g*. We used two spectra at disk centre ($\mu$ = 1.0), from Delbouille and Kurucz, and two spectra at the limb from Stenflo and Gandorfer, respectively at $\mu$ = 0.145 and $\mu$ = 0.10.

Aims. The aim of this paper is to consider relationship between the decay of sunspots and convection via the motion of the family of granules and how the diffusion mechanism of magnetic field operates in a decaying sunspot. Methods. We report the decay of a sunspot observed by the 1.6m Goode Solar Telescope (GST) with the TiO Broadband Filter Imager (BFI) and the Near-InfraRed Imaging Spectropolarimeter (NIRIS). The analysis was aided by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamic Observatory (SDO). In the first step, we followed the decay of the sunspot with HMI data over three days by constructing its evolving area and total magnetic flux. In the second step, the high spatial and temporal resolution of the GST instruments allowed us to analyze the causes of the decay of the sunspot. Afterward, we followed the emergence of granules in the moat region around the sunspot over six hours. The evolution of the trees of fragmenting granules (TFGs) was derived based on their relationship with the horizontal surface flows. Results. We find that the area and total magnetic flux display an exponential decrease over the course of the sunspot decay. We identified 22 moving magnetic features (MMFs) in the moats of pores, which is a signature of sunspot decay through diffusion. We note that the MMFs were constrained to follow the borders of TFGs during their journey away from the sunspot. Conclusions. The TFGs and their development contribute to the diffusion of the magnetic field outside the sunspot. The conclusion of our analysis shows the important role of the TFGs in sunspot decay. Finally, the the family of granules evacuates the magnetic field.

The spectroheliograph was invented independently by Henri Deslandres (France) and George Hale (USA) in 1892, following the spectroscopic method suggested by Jules Janssen in 1869. This instrument is dedicated to the production of monochromatic images of the Sun in order to reveal the structures of the photosphere and the chromosphere at various altitudes. Sporadic observations started in Paris, but Deslandres moved soon to Meudon and designed, with Lucien d'Azambuja, an universal and powerful instrument, the quadruple spectroheliograph. It was devoted to systematic observations of the Sun (the long-term activity survey since 1908) and scientific research in solar physics. This paper describes the instrument and presents some original observations made with the high dispersion 7-metre spectrograph. It was dismantled in the sixties, but the solar patrol continued with the 3-metre chambers with H$\alpha$ and CaII K lines, and is still working today with the numerical version of the spectroheliograph., Comment: arXiv admin note: text overlap with arXiv:2303.05149

Neural Information Retrieval (NIR) has significantly improved upon heuristic-based IR systems. Yet, failures remain frequent, the models used often being unable to retrieve documents relevant to the user's query. We address this challenge by proposing a lightweight abstention mechanism tailored for real-world constraints, with particular emphasis placed on the reranking phase. We introduce a protocol for evaluating abstention strategies in a black-box scenario, demonstrating their efficacy, and propose a simple yet effective data-driven mechanism. We provide open-source code for experiment replication and abstention implementation, fostering wider adoption and application in diverse contexts.

Bernard Lyot invented the monochromatic birefringent filter in 1933 in order to investigate the coronal emissions of solar structures above the limb with the coronagraph installed at the Pic du Midi observatory. The filter was improved later and he made the first observations of the chromosphere above the solar disk in 1948, at Meudon. After his death, Grenat and Laborde continued the development in the frame of the coming International Geophysical Year (IGY 1957-1958). A modern H$\alpha$ heliograph was completed soon and the flare patrol started in 1956. This instrument was reproduced by two companies (SECASI and OPL) and disseminated around the world in order to contribute to the IGY common effort dedicated to the solar activity survey. We describe in this short paper the capabilities of one of these copies operating at Haute Provence station from 1958 to 1994.

Synthetic Minority Oversampling Technique (SMOTE) is a common rebalancing strategy for handling imbalanced tabular data sets. However, few works analyze SMOTE theoretically. In this paper, we prove that SMOTE (with default parameter) simply copies the original minority samples asymptotically. We also prove that SMOTE exhibits boundary artifacts, thus justifying existing SMOTE variants. Then we introduce two new SMOTE-related strategies, and compare them with state-of-the-art rebalancing procedures. Surprisingly, for most data sets, we observe that applying no rebalancing strategy is competitive in terms of predictive performances, with tuned random forests. For highly imbalanced data sets, our new method, named Multivariate Gaussian SMOTE, is competitive. Besides, our analysis sheds some lights on the behavior of common rebalancing strategies, when used in conjunction with random forests.

The Sun has been observed through a telescope for four centuries. However, its study made a prodigious leap at the end of the nineteenth century with the appearance of photography and spectroscopy, then at the beginning of the following century with the invention of the coronagraph and monochromatic filters, and finally in the second half of the twentieth century with the advent of space exploration (satellites, probes). This makes it possible to observe the radiations hidden by the Earth's atmosphere (Ultra Violet, X-rays, $\gamma$) and to carry out ''in situ'' measurements in the solar environment. This article retraces the major stages of this fantastic epic in which renowned scientists such as Janssen, Deslandres, d'Azambuja, Lyot and Dollfus entered the scene, giving the Paris-Meudon Observatory a pioneering role in the history of solar physics until 1960. After this golden age, space exploration required large resources shared between nations, which could no longer be implemented within teams or even individual institutes. The development of numerical simulation, a new research tool, also required the pooling of supercomputers.

Imaging spectroscopy is intended to be coupled with adaptive optics (AO) on large solar telescopes, in order to produce high spatial and temporal resolution measurements of velocities and magnetic fields on a 2D target. We present the theoretical capabilities of a new generation 24-channel MSDP slicer for 8-meter class spectrographs which are common in solar astronomy. The aim is to produce 24-channel spectra-images providing cubes of instantaneous data (x, y, $\lambda$) allowing the study of the plasma dynamics and magnetic fields. We investigate the possibility of doubling the spectral resolution using two interlaced spectra-images, delivering together 48 channels. Two polarimetric methods are also explored providing simultaneous measurements of Stokes combinations with a dual beam; one of them could provide 48 sub-channels (or 96 with wavelength interlaced observations).

The Meudon Solar Tower (MST) is a 0.60 m telescope dedicated to spectroscopic observations of solar regions. It includes a 14-meter focal length spectrograph which offers high spectral resolution. The spectrograph works either in classical thin slit mode (R > 300000) or 2D imaging spectroscopy (60000 < R < 180000). This specific mode is able to provide high temporal resolution measurements (1 min) of velocities and magnetic fields upon a 2D field of view, using the Multichannel Subtractive Double Pass (MSDP) system. The purpose of this paper is to describe the capabilities of the MSDP at MST with available slicers for broad and thin lines. The goal is to produce multichannel spectra-images, from which cubes of instantaneous data (x, y, $\lambda$) are derived, in order to study of the plasma dynamics and magnetic fields (with polarimetry).

Imaging spectroscopy is intended to be coupled with adaptive optics (AO) on large telescopes, such as EST, in order to produce high spatial and temporal resolution measurements of velocities and magnetic fields upon a 2D FOV. We propose a high spectral resolution slicer (30 m{\AA} typical) for the Multichannel Subtractive Double Pass (MSDP) of the future European Solar Telescope (EST), using a new generation slicer for thin photospheric lines such as FeI (56 channels, 0.13 mm step) which will benefit of AO and existing polarimeters. The aim is to reconstitute cubes of instantaneous data (X, Y, lambda) at high cadence, allowing the study of the photospheric dynamics and magnetic fields.

We present a polymorphic linear lambda-calculus as a proof language for second-order intuitionistic linear logic. The calculus includes addition and scalar multiplication, enabling the proof of a linearity result at the syntactic level., Comment: arXiv admin note: substantial text overlap with arXiv:2201.11221

Imaging spectroscopy is intended to be coupled with adaptive optics (AO) on large telescopes, such as EST, in order to produce high spatial and temporal resolution measurements of velocities and magnetic fields upon a 2D FOV. We propose a Multichannel Subtractive Double Pass (MSDP) incorporated to the EST visible and IR spectrographs, using new generation slicers (56 channels, high spectral resolution) which will benefit of AO and polarimeters. The aim is to produce 56-channel spectra images with the spatial resolution of the AO and reconstitute cubes of instantaneous data (X, Y, lambda) at high cadence, allowing the study of the plasma dynamics and magnetic fields. The MSDP is compatible with most polarimetric methods (we shall discuss only two of them).

Full disc observations of the Sun in the H$\alpha$ line provide information about the solar chromosphere and in particular about the filaments, which are dark and elongated features that lie along magnetic field polarity inversion lines. This makes them important for studies of solar magnetism. Since full disc H$\alpha$ observations have been performed at various sites since 1800s, with regular photographic data having started in the beginning of the 20th century, they are an invaluable source of information on past solar magnetism. In this work we aimed at deriving accurate information about filaments from historical and modern full disc H$\alpha$ observations. We have consistently processed observations from 15 H$\alpha$ archives spanning 1909-2022. Our data processing includes photometric calibration of the data stored on photographic plates. We have constructed also Carrington maps from the calibrated H$\alpha$ images. We find that filament areas are affected by the bandwidth of the observation. Thus, cross-calibration of the filament areas derived from different archives is needed. We have produced a composite of filament areas from individual archives by scaling all of them to the Meudon series. Our composite butterfly diagram shows very distinctly the common features of filament evolution, that is the poleward migration as well as a decrease in the mean latitude of filaments as the cycle progresses. We also find that during activity maxima, filaments on average cover about 1% of the solar surface. We see only a weak change in the amplitude of cycles in filament areas, in contrast to sunspot and plage areas. Analysis of H$\alpha$ data for archives with contemporaneous Ca II K observations allowed us to identify and verify archive inconsistencies, which will also have implications for reconstructions of past solar magnetism and irradiance from Ca II K data., Comment: 21 pages, 14 figures, accepted for publication in A&A

We consider the linear lambda-calculus extended with the sup type constructor, which provides an additive conjunction along with a non-deterministic destructor. The sup type constructor has been introduced in the context of quantum computing. In this paper, we study this type constructor within a simple linear logic categorical model, employing the category of semimodules over a commutative semiring. We demonstrate that the non-deterministic destructor, either weighted or not, finds a suitable model in a weighted codiagonal map. Our approach offers a valid and insightful alternative to interpreting non-determinism and probability calculi, in instances where the conventional Moggi's Powerset Monad interpretation does not align with the category's structure, as is the case with the category of semimodules. The validity of this alternative relies on the presence of biproducts within the category., Comment: There is a mistake in the adequacy proof for the first language. The other languages have been integrated into arXiv:2205.02142, making this paper merely a concrete example

We study by numerical simulation the magnetic order in ensembles of randomly packed magnetic spherical particles which, induced by their uniaxial anisotropy in the strong coupling limit, behave as Ising dipoles. We explore the role of the frozen disorder in the positions of the particles assuming a common fixed direction for the easy axes of all spheres. We look at two types of spatially disordered configurations. In the first one we consider isotropic positional distributions which can be obtained from the liquid state of the hard sphere fluid. We derive the phase diagram in the $T$-$\Phi$ plane where $T$ is the temperature and $\Phi$ the volume fraction. This diagram exhibits long-range ferromagnetic order at low $T$ for volume fractions above the threshold $\Phi_{c} = 0.157$ predicted by mean-field calculations. For $\Phi \lesssim \Phi_{c}$ a spin-glass phase forms with the same marginal behavior found for other strongly disordered dipolar systems. The second type of spatial configurations we study are anisotropic distributions that can be obtained by freezing a dipolar hard sphere liquid in its polarized state at low temperature. This structural anisotropy enhances the ferromagnetic order present in isotropic hard sphere configurations., Comment: 10 pages, 13 figures

Systematic observations of the chromosphere and the photosphere started in Meudon Observatory 115 years ago with Deslandres spectroheliograph. An exceptional collection of more than 100 000 monochromatic images in CaII K and H$\alpha$ spanning more than 10 solar cycles is proposed to the international community by the BASS2000 solar database. We started in 2023 a ''PRO-AM'' collaboration between professional and amateur astronomers with the Solar Explorer (SOLEX), a compact and high quality spectroheliograph designed by Christian Buil, in order to record images every day, and several times per day, owing to tens of observing stations in various places. This paper summarizes the scientific objectives and provides practical and technical information to amateurs willing to join the observing network., Comment: arXiv admin note: text overlap with arXiv:2301.11105

We summarize in this paper the spectro-polarimetric methods used at the Pic du Midi Turret Dome in spectroscopic or imagery mode. The polarimeters and spectrograph allow the cartography of solar magnetic fields at high spatial resolution through the Zeeman effect or measurements of the unresolved turbulent magnetic fields in the quiet Sun through the Hanle effect. We describe in this paper the optical capabilities of the successive versions of the polarimeters operating since 2003, and we present new results of magnetic field analysis with the CaII K 3933.7 {\AA} spectral line.

H$\alpha$ heliographs are imaging instruments designed to produce monochromatic images of the solar chromosphere at fast cadence (60 s or less). They are designed to monitor efficiently dynamic phenomena of solar activity, such as flares or material ejections. Meudon and Haute Provence observatories started systematic observations in the frame of the International Geophysical Year (1957) with Lyot filters. This technology evolved several times until 1985 with tunable filters allowing to observe alternatively the line wings and core (variable wavelength). More than 6 million images were produced during 50 years, mostly on 35 mm films (catalogs are available on-line). We present in this paper the optical characteristics and the capabilities of the successive versions of the H$\alpha$ heliographs in operation between 1954 and 2004, and describe briefly the new heliograph (MeteoSpace) which will be commissioned in 2023 at Calern observatory.

The spectroheliograph is a spectroscopic instrument designed to produce monochromatic images of the photosphere (the visible layer) and the chromosphere of the Sun. It was invented at the same time (1892), but independently, by Hale in the USA and Deslandres in France and was dedicated to long-term surveys of the solar cycles. For that purpose, systematic observations of the CaII K and H$\alpha$ lines started in Meudon observatory in 1908 and continue today, so that a huge collection of more than 100000 spectroheliograms, spanning 115 years of solar activity, was recorded. We present in this paper the optical characteristics and the capabilities of the successive versions of the instrument, from 1908 to now.

Henri Deslandres initiated imaging spectroscopy of the solar atmosphere in 1892 at Paris observatory. He invented, concurrently with George Hale in Kenwood (USA) but quite independently, the spectroheliograph designed for monochromatic imagery of the Sun. Deslandres developed two kinds of spectrographs: the ''spectroh{\'e}liographe des formes'', i.e. the narrow bandpass instrument to reveal chromospheric structures (such as filaments, prominences, plages and active regions); and the ''spectroh{\'e}liographe des vitesses'', i.e. the ''section'' spectroheliograph to record line profiles of cross sections of the Sun, in order to measure the Dopplershifts of dynamic features. Deslandres moved to Meudon in 1898 with his instruments and improved the spectral and spatial resolutions, leading to the large quadruple spectroheliograph in 1908 developed with Lucien d'Azambuja. CaII K systematic observations started at this date and were followed in 1909 by H$\alpha$ with two dedicated 3-metres spectroheliographs. The observing service was organized by d'Azambuja who also intensively used the large 7-metres spectroheliograph for his research and thesis (1930). This paper summarizes fifty years of research by Mr and Mrs d'Azambuja, who explored various photospheric and chromospheric lines, performing special spectroheliograms with the high dispersion 7-metres instrument. They also observed intensively filaments and prominences (memoir published in 1948) and recorded rare solar activity events with the two 3-metres spectroheliographs, during the first half of the twentieth century., Comment: arXiv admin note: text overlap with arXiv:2301.11105

We present in this reference paper an instrumental project dedicated to the monitoring of solar activity during solar cycle 25. It concerns the survey of fast evolving chromospheric events implied in Space Weather, such as flares, coronal mass ejections, filament instabilities and Moreton waves. Coronal waves are produced by large flares around the solar maximum and propagate with chromospheric counterparts; they are rare, faint, difficult to observe, and for that reason, challenging. They require systematic observations with automatic, fast and multi-channel optical instruments. MeteoSpace is a high cadence telescope assembly specially designed for that purpose. The large amount of data will be freely available to the solar community. We describe in details the optical design, the qualification tests and capabilities of the telescopes, and show how waves can be detected. MeteoSpace will be installed at Calern observatory (C{\^o}te d'Azur, 1270 m) and will be in full operation in 2023.

Broad-band observations of the solar photosphere began in Meudon in 1875 under the auspices of Jules Janssen. For his part, Henri Deslandres initiated imaging spectroscopy in 1892 at Paris observatory. He invented, concurrently with George Hale in Kenwood (USA) but quite independently, the spectroheliograph designed for monochromatic imagery of the solar atmosphere. Deslandres developed two kinds of spectrographs: the ''spectroh{\'e}liographe des formes'', i.e. the narrow bandpass instrument to reveal chromospheric structures (such as filaments, prominences, plages and active regions); and the ''spectroh{\'e}liographe des vitesses'', i.e. the section spectroheliograph to record line profiles of cross sections of the Sun with a 20''-30'' spatial step. This second apparatus was intended to measure the velocities (more exactly the Dopplershifts) of dynamic features. Deslandres moved to Meudon in 1898 with his instruments and tested various combinations, in order to improve the spectral and spatial resolutions, leading to the final large quadruple spectroheliograph in 1908. CaII K systematic observations started at this date and were followed in 1909 by H$\alpha$. The service was organized by Lucien d'Azambuja and continues today. Optical and mechanical parts were revisited in 1989 and the digital technology was introduced in 2002. Full line profiles are registered for all pixels of the Sun since 2018, so that the instrument produces now data-cubes. The collection is one of the longest available (more than 100 000 observations). It contains sporadic images from 1893 to 1907 (during the development phase) and systematic observations along 10 solar cycles since 1908, in H$\alpha$ and CaII K lines. This paper summarizes 130 years of observations, instrumental research and technical advances.

Detailed knowledge of surface dynamics is one of the key points in understanding magnetic solar activity. The motions of the solar surface, to which we have direct access via the observations, tell us about the interaction between the emerging magnetic field and the turbulent fields. The flows computed with the coherent structure tracking (CST) technique on the whole surface of the Sun allow for the texture of the velocity modulus to be analyzed and for one to locate the largest horizontal flows and determine their organization. The velocity modulus maps show structures more or less circular and closedwhich are visible at all latitudes; here they are referred to as donuts. They reflect the most active convective cells associated with supergranulation. These annular flows are not necessarily joined as would seem to indicate the divergence maps. The donuts have identical properties (amplitude, shape, inclination, etc.) regardless of their position on the Sun. The kinematic simulation of the donuts' outflow applied to passive scalar (corks) indicates the preponderant action of the selected donuts which are, from our analysis, one of the major actors for the magnetic field diffusion on the quiet Sun. The absence of donuts in the magnetized areas (plages) indicates the action of the magnetic field on the strongest supergranular flows and thus modifies the diffusion of the magnetic field in that location. The detection of the donuts is a way to locate in the quiet Sun the vortex and the link with the jet, blinkers, coronal bright points (campfires), or other physical structures. Likewise, the study of the influence of donuts on the evolution of active events, such as the destruction of sunspots, filament eruptions, and their influences on upper layers via spicules and jets, could be done more efficiently via the detection of that structures., Comment: 14 pages, 17 figures

We study the magnetic phase diagram of an ensemble of dipolar hard spheres (DHS) with or without uniaxial anisotropy and frozen in position on a disordered structure by tempered Monte Carlo simulations. The crucial point is to consider an anisotropic structure, obtained from the liquid state of the dipolar hard spheres fluid, frozen in its polarized state at low temperature. The freezing inverse temperature $\beta_f$ determines the degree of anisotropy of the structure which is quantified through a structural nematic order parameter, $\lambda_s$. The case of the non zero uniaxial anisotropy is considered only in its infinitely strong strength limit where the system transforms in a dipolar Ising model (DIM). The important finding of this work is that both the DHS and the DIM with a frozen structure build in this way present a ferromagnetic phase at volume fractions below the threshold value where the corresponding isotropic DHS systems exhibit a spin glass phase at low temperature., Comment: 12 pages, 15 figures

Studies and reconstructions of past solar activity require data on sunspots as well as faculae/plage and network. Such data are also important for understanding the magnetic activity and variability of the Sun and Sun-like stars. The longest available direct faculae/plage datasets are white-light facular and Ca II K observations going back to 1874 and 1892, respectively. Prior to that time, the only direct data available are for sunspots. We reassess the relationship between plage areas and sunspot records (areas and numbers) since 1892, to allow reconstructions of facular/plage areas which can be employed for studies going further back in time, i.e. over the period when solely sunspot observations are available. We use the plage areas derived from 38 consistently processed Ca II K archives as well as the plage area composite based on these archives. We find the relationship between plage and sunspot areas and numbers to be well represented by a power law function. We further find that the relationships depend on the bandwidth and the solar cycle strength. The reconstructions with a power law relationship are in good agreement with the original plage area series, whereas employment of a cycle-strength-dependent relationship improves the reconstructions only marginally. Performing the same analysis on other previously published plage area series, usually derived from a single archive with diverse processing techniques, returns different results when using different time series. This highlights the importance of applying a consistent processing to the various archives and demonstrates the uncertainties introduced by using previously published series. Our results have implications for past solar activity and irradiance reconstructions as well as for stellar activity studies, which sometimes assume a linear dependence between plage and sunspot areas., Comment: 22 pages, 13 figures, accepted for publication in Astronomy & Astrophysics

We explore a proof language for intuitionistic multiplicative additive linear logic, incorporating the sup connective that introduces additive pairs with a probabilistic elimination, and sum and scalar products within the proof-terms. We provide an abstract characterization of the language, revealing that any symmetric monoidal closed category with biproducts and a monomorphism from the semiring of scalars to the semiring Hom(I,I) is suitable for the job. Leveraging the binary biproducts, we define a weighted codiagonal map at the heart of the sup connective.

We introduce Perceval, an open-source software platform for simulating and interfacing with discrete-variable photonic quantum computers, and describe its main features and components. Its Python front-end allows photonic circuits to be composed from basic photonic building blocks like photon sources, beam splitters, phase-shifters and detectors. A variety of computational back-ends are available and optimised for different use-cases. These use state-of-the-art simulation techniques covering both weak simulation, or sampling, and strong simulation. We give examples of Perceval in action by reproducing a variety of photonic experiments and simulating photonic implementations of a range of quantum algorithms, from Grover's and Shor's to examples of quantum machine learning. Perceval is intended to be a useful toolkit for experimentalists wishing to easily model, design, simulate, or optimise a discrete-variable photonic experiment, for theoreticians wishing to design algorithms and applications for discrete-variable photonic quantum computing platforms, and for application designers wishing to evaluate algorithms on available state-of-the-art photonic quantum computers., Comment: 52 pages, supplementary code in the appendices