Edit Profile (opens in new tab) Šlapal, Josef Co-Author Distance Author ID: slapal.josef Published as: Šlapal, Josef; Šlapal, J.; Slapal, Josef; Slapal, J. more...less External Links: ORCID Documents Indexed: 121 Publications since 1984, including 1 Additional arXiv Preprint 1 Contribution as Editor Co-Authors: 13 Co-Authors with 21 Joint Publications 202 Co-Co-Authors all top 5 Co-Authors 101 single-authored 4 Holgate, David B. 4 Richmond, Thomas A. 3 Iragi, Minani 2 Bednařík, František 2 Chaisansuk, Nitima 2 Giuli, Eraldo 2 Pfaltz, John L. 1 Barneva, Reneta P. 1 Boonpok, Chawalit 1 Brimkov, Valentin E. 1 Kureš, Miroslav 1 Leeratanavalee, Sorasak 1 Novotný, Miroslav all top 5 Serials 7 Mathematica Slovaca 6 Applied Categorical Structures 5 Quaestiones Mathematicae 5 Topology Proceedings 5 Filomat 4 Czechoslovak Mathematical Journal 4 Publicationes Mathematicae Debrecen 4 Topology and its Applications 4 Aequationes Mathematicae 3 Demonstratio Mathematica 3 Mathematische Nachrichten 3 Acta Mathematica Hungarica 3 Mathematica Pannonica 3 Open Mathematics 2 Discrete Applied Mathematics 2 Theoretical Computer Science 2 New Zealand Journal of Mathematics 2 East-West Journal of Mathematics 2 Hacettepe Journal of Mathematics and Statistics 2 Mathematics for Applications 1 Periodica Mathematica Hungarica 1 Revue Roumaine de Mathématiques Pures et Appliquées 1 Beiträge zur Algebra und Geometrie 1 Acta Scientiarum Mathematicarum 1 Algebra Universalis 1 Annales Universitatis Scientiarum Budapestinensis de Rolando Eötvös Nominatae. Sectio Mathematica 1 Archiv der Mathematik 1 Archivum Mathematicum 1 Collectanea Mathematica 1 Information Sciences 1 Journal of Computer and System Sciences 1 Monatshefte für Mathematik 1 Rendiconti del Seminario Matematico della Università di Padova 1 Zeitschrift für Mathematische Logik und Grundlagen der Mathematik 1 Annales Societatis Mathematicae Polonae. Seria I. Commentationes Mathematicae 1 Acta Mathematica Universitatis Comenianae 1 Note di Matematica 1 Prace Naukowe Uniwersytetu Śląskiego w Katowicach. Annales Mathematicae Silesianae 1 Mathematica Bohemica 1 International Journal of Computer Mathematics 1 Tatra Mountains Mathematical Publications 1 Computational and Applied Mathematics 1 Turkish Journal of Mathematics 1 Annals of Mathematics and Artificial Intelligence 1 Analele Științifice ale Universității “Ovidius” Constanța. Seria: Matematică 1 Discrete Mathematics and Theoretical Computer Science. DMTCS 1 Fundamenta Informaticae 1 Discussiones Mathematicae. General Algebra and Applications 1 Bulletin of the Malaysian Mathematical Sciences Society. Second Series 1 Cahiers de Topologie et Géométrie Différentielle Catégoriques 1 Thai Journal of Mathematics 1 Miskolc Mathematical Notes 1 Carpathian Journal of Mathematics 1 Lecture Notes in Computer Science 1 TWMS Journal of Pure and Applied Mathematics all top 5 Fields 66 General topology (54-XX) 41 Category theory; homological algebra (18-XX) 31 Computer science (68-XX) 27 General algebraic systems (08-XX) 16 Combinatorics (05-XX) 13 Order, lattices, ordered algebraic structures (06-XX) 8 Convex and discrete geometry (52-XX) 7 Mathematical logic and foundations (03-XX) 2 History and biography (01-XX) 1 General and overarching topics; collections (00-XX) 1 Group theory and generalizations (20-XX) 1 Topological groups, Lie groups (22-XX) 1 Numerical analysis (65-XX) 1 Operations research, mathematical programming (90-XX) 1 Information and communication theory, circuits (94-XX) Publications by Year all cited Publications top 5 cited Publications Citations contained in zbMATH Open 68 Publications have been cited 290 times in 127 Documents Cited by ▼ Year ▼ Categorical neighborhood operators. Zbl 1232.54018 Holgate, David; Šlapal, Josef 22 2011 Closure operations for digital topology. Zbl 1081.68111 Šlapal, J. 21 2003 Digital Jordan curves. Zbl 1111.54021 Šlapal, Josef 20 2006 Neighborhoods with respect to a categorical closure operator. Zbl 1265.18014 Giuli, E.; Šlapal, J. 14 2009 A digital analogue of the Jordan curve theorem. Zbl 1062.54001 Šlapal, J. 13 2004 Topological structuring of the digital plane. Zbl 1285.68190 Šlapal, Josef 12 2013 A quotient-universal digital topology. Zbl 1155.54015 Šlapal, Josef 11 2008 Graphs with a path partition for structuring digital spaces. Zbl 1284.05310 Šlapal, Josef 10 2013 Relations and topologies. Zbl 0797.04002 Šlapal, Josef 10 1993 Convenient closure operators on \(\mathbb Z^2\). Zbl 1267.68257 Šlapal, Josef 9 2009 Jordan curve theorems with respect to certain pretopologies on \(\mathbb Z^2\). Zbl 1261.68118 Šlapal, Josef 8 2009 Net spaces in categorical topology. Zbl 0902.54008 Šlapal, Josef 7 1996 Convergence structures for categories. Zbl 1006.18005 Šlapal, Josef 7 2001 Compactness with respect to a convergence structure. Zbl 1006.18006 Šlapal, Josef 5 2002 Direct arithmetics of relational systems. Zbl 0733.08001 Šlapal, Josef 5 1991 On categories of ordered sets with a closure operator. Zbl 1240.18016 Šlapal, Josef 5 2011 Compactness and convergence with respect to a neighborhood operator. Zbl 1256.54034 Šlapal, Josef 5 2012 A Galois correspondence between closure spaces and relational systems. Zbl 0932.06005 Šlapal, Josef 5 1998 Compactification of limit \(\mathcal S\)-net spaces. Zbl 0978.54017 Šlapal, Josef 4 2001 Compactness in categories of \(\mathcal S\)-net spaces. Zbl 0917.54029 Šlapal, Josef 4 1998 Raster convergence with respect to a closure operator. Zbl 1106.54006 Giuli, E.; Slapal, J. 4 2005 Convergence on categories. Zbl 1158.18002 Šlapal, Josef 4 2008 On closure operations induced by binary relations. Zbl 0658.54002 Šlapal, Josef 4 1988 Cardinal arithmetic of general relational systems. Zbl 0797.04001 Šlapal, Josef 4 1993 On exponentiation of \(n\)-ary algebras. Zbl 0798.08001 Šlapal, J. 4 1994 \(F\)-net convergence with respect to a closure operator. Zbl 1069.18005 Šlapal, Josef 3 2005 Relations of type \(\alpha\). Zbl 0668.04002 Šlapal, Josef 3 1988 A note of F-topologies. Zbl 0712.54001 Šlapal, Josef 3 1989 A Jordan curve theorem in the digital plane. Zbl 1330.68317 Slapal, Josef 3 2011 A Jordan curve theorem with respect to certain closure operations on the digital plane. Zbl 1260.68423 Šlapal, Josef 3 2001 Neighborhoods and convergence with respect to a closure operator. Zbl 1274.18015 Šlapal, Josef 3 2011 Path-set induced closure operators on graphs. Zbl 1462.05313 Šlapal, Josef 3 2016 Relation-induced connectedness in the digital plane. Zbl 1390.68732 Šlapal, Josef 3 2018 A closure operator for the digital plane. Zbl 1499.54219 Šlapal, Josef 3 2020 On the direct power of relational systems. Zbl 0686.08001 Šlapal, Josef 3 1989 A categorical approach to convergence: compactness. Zbl 1333.18011 Šlapal, Josef 2 2016 On a product of universal hyperalgebras. Zbl 1349.08006 Chaisansuk, Nitima; Šlapal, Josef 2 2015 On exponentiation of universal hyperalgebras. Zbl 1013.08008 Šlapal, Josef 2 2000 Closure operators associated with networks. Zbl 1368.05138 Šlapal, Josef; Pfaltz, John L. 2 2017 On powers of relational structures. Zbl 1012.08004 Novotný, Miroslav; Šlapal, Josef 2 2002 On the stability of some properties of partial algebras under powers. Zbl 1313.08003 Chaisansuk, N.; Leeratanavalee, S.; Šlapal, J. 2 2014 Cartesian closedness in categories of relational systems. Zbl 0677.18007 Šlapal, Josef 2 1989 On relations. Zbl 0682.04001 Šlapal, Josef 2 1989 Exponentiality in concrete categories. Zbl 0793.18004 Šlapal, Josef 2 1993 Closure operators on graphs for modeling connectedness in digital spaces. Zbl 1499.54220 Šlapal, Josef 2 2018 Exponentiation of relational systems with respect to strong homomorphisms. Zbl 0929.08001 Bednařík, František; Šlapal, Josef 1 1999 Exponentiality in categories of partial algebras. Zbl 1006.08006 Šlapal, Josef 1 2002 Convenient adjacencies for structuring the digital plane. Zbl 1321.05139 Šlapal, Josef 1 2015 A note on general relations. Zbl 0839.04002 Šlapal, Josef 1 1995 A Galois correspondence for digital topology. Zbl 1069.18006 Šlapal, J. 1 2004 Convenient adjacencies on \(\mathbb Z^2\). Zbl 1464.05219 Šlapal, Josef 1 2014 On embeddings of relational categories into algebraic categories. Zbl 0834.18003 Šlapal, Josef 1 1993 A categorical approach to convergence. Zbl 1461.54019 Šlapal, Josef 1 2016 A conglomerate of exponential supercategories of the category of finitely generated topological spaces. Zbl 0814.18001 Šlapal, Josef 1 1995 A Cartesian closed topological category of sequential spaces. Zbl 0724.18007 Šlapal, J. 1 1990 Adjacencies for structuring the digital plane. Zbl 1377.68291 Šlapal, Josef 1 2012 Jordan curves in the digital plane. Zbl 1297.68249 Šlapal, Josef 1 2014 A note on diagonality of algebras. Zbl 0770.08002 Šlapal, Josef 1 1992 A Jordan curve theorem with respect to a pretopology on \(\mathbb Z^2\). Zbl 1280.54014 Šlapal, Josef 1 2013 Neighborhood spaces and convergence. Zbl 1201.54004 Richmond, Tom; Šlapal, Josef 1 2010 Neighborhood spaces and convergence. Zbl 1201.54005 Richmond, Tom; Šlapal, Josef 1 2010 Galois connections between sets of paths and closure operators in simple graphs. Zbl 1407.05070 Šlapal, Josef 1 2018 Walk-set induced connectedness in digital spaces. Zbl 1399.05138 Šlapal, Josef 1 2017 Another approach to connectedness with respect to a closure operator. Zbl 1184.54014 Šlapal, J. 1 2009 Path-induced closure operators on graphs for defining digital Jordan surfaces. Zbl 1513.54128 Šlapal, Josef 1 2019 Closure, interior and neighbourhood in a category. Zbl 1488.18004 Holgate, David; Slapal, Josef 1 2018 On the axioms preserved by modifications of topologies without axioms. Zbl 0681.54003 Šlapal, Josef 1 1988 A 3D digital Jordan-Brouwer separation theorem. Zbl 1463.68135 Šlapal, Josef 1 2020 A closure operator for the digital plane. Zbl 1499.54219 Šlapal, Josef 3 2020 A 3D digital Jordan-Brouwer separation theorem. Zbl 1463.68135 Šlapal, Josef 1 2020 Path-induced closure operators on graphs for defining digital Jordan surfaces. Zbl 1513.54128 Šlapal, Josef 1 2019 Relation-induced connectedness in the digital plane. Zbl 1390.68732 Šlapal, Josef 3 2018 Closure operators on graphs for modeling connectedness in digital spaces. Zbl 1499.54220 Šlapal, Josef 2 2018 Galois connections between sets of paths and closure operators in simple graphs. Zbl 1407.05070 Šlapal, Josef 1 2018 Closure, interior and neighbourhood in a category. Zbl 1488.18004 Holgate, David; Slapal, Josef 1 2018 Closure operators associated with networks. Zbl 1368.05138 Šlapal, Josef; Pfaltz, John L. 2 2017 Walk-set induced connectedness in digital spaces. Zbl 1399.05138 Šlapal, Josef 1 2017 Path-set induced closure operators on graphs. Zbl 1462.05313 Šlapal, Josef 3 2016 A categorical approach to convergence: compactness. Zbl 1333.18011 Šlapal, Josef 2 2016 A categorical approach to convergence. Zbl 1461.54019 Šlapal, Josef 1 2016 On a product of universal hyperalgebras. Zbl 1349.08006 Chaisansuk, Nitima; Šlapal, Josef 2 2015 Convenient adjacencies for structuring the digital plane. Zbl 1321.05139 Šlapal, Josef 1 2015 On the stability of some properties of partial algebras under powers. Zbl 1313.08003 Chaisansuk, N.; Leeratanavalee, S.; Šlapal, J. 2 2014 Convenient adjacencies on \(\mathbb Z^2\). Zbl 1464.05219 Šlapal, Josef 1 2014 Jordan curves in the digital plane. Zbl 1297.68249 Šlapal, Josef 1 2014 Topological structuring of the digital plane. Zbl 1285.68190 Šlapal, Josef 12 2013 Graphs with a path partition for structuring digital spaces. Zbl 1284.05310 Šlapal, Josef 10 2013 A Jordan curve theorem with respect to a pretopology on \(\mathbb Z^2\). Zbl 1280.54014 Šlapal, Josef 1 2013 Compactness and convergence with respect to a neighborhood operator. Zbl 1256.54034 Šlapal, Josef 5 2012 Adjacencies for structuring the digital plane. Zbl 1377.68291 Šlapal, Josef 1 2012 Categorical neighborhood operators. Zbl 1232.54018 Holgate, David; Šlapal, Josef 22 2011 On categories of ordered sets with a closure operator. Zbl 1240.18016 Šlapal, Josef 5 2011 A Jordan curve theorem in the digital plane. Zbl 1330.68317 Slapal, Josef 3 2011 Neighborhoods and convergence with respect to a closure operator. Zbl 1274.18015 Šlapal, Josef 3 2011 Neighborhood spaces and convergence. Zbl 1201.54004 Richmond, Tom; Šlapal, Josef 1 2010 Neighborhood spaces and convergence. Zbl 1201.54005 Richmond, Tom; Šlapal, Josef 1 2010 Neighborhoods with respect to a categorical closure operator. Zbl 1265.18014 Giuli, E.; Šlapal, J. 14 2009 Convenient closure operators on \(\mathbb Z^2\). Zbl 1267.68257 Šlapal, Josef 9 2009 Jordan curve theorems with respect to certain pretopologies on \(\mathbb Z^2\). Zbl 1261.68118 Šlapal, Josef 8 2009 Another approach to connectedness with respect to a closure operator. Zbl 1184.54014 Šlapal, J. 1 2009 A quotient-universal digital topology. Zbl 1155.54015 Šlapal, Josef 11 2008 Convergence on categories. Zbl 1158.18002 Šlapal, Josef 4 2008 Digital Jordan curves. Zbl 1111.54021 Šlapal, Josef 20 2006 Raster convergence with respect to a closure operator. Zbl 1106.54006 Giuli, E.; Slapal, J. 4 2005 \(F\)-net convergence with respect to a closure operator. Zbl 1069.18005 Šlapal, Josef 3 2005 A digital analogue of the Jordan curve theorem. Zbl 1062.54001 Šlapal, J. 13 2004 A Galois correspondence for digital topology. Zbl 1069.18006 Šlapal, J. 1 2004 Closure operations for digital topology. Zbl 1081.68111 Šlapal, J. 21 2003 Compactness with respect to a convergence structure. Zbl 1006.18006 Šlapal, Josef 5 2002 On powers of relational structures. Zbl 1012.08004 Novotný, Miroslav; Šlapal, Josef 2 2002 Exponentiality in categories of partial algebras. Zbl 1006.08006 Šlapal, Josef 1 2002 Convergence structures for categories. Zbl 1006.18005 Šlapal, Josef 7 2001 Compactification of limit \(\mathcal S\)-net spaces. Zbl 0978.54017 Šlapal, Josef 4 2001 A Jordan curve theorem with respect to certain closure operations on the digital plane. Zbl 1260.68423 Šlapal, Josef 3 2001 On exponentiation of universal hyperalgebras. Zbl 1013.08008 Šlapal, Josef 2 2000 Exponentiation of relational systems with respect to strong homomorphisms. Zbl 0929.08001 Bednařík, František; Šlapal, Josef 1 1999 A Galois correspondence between closure spaces and relational systems. Zbl 0932.06005 Šlapal, Josef 5 1998 Compactness in categories of \(\mathcal S\)-net spaces. Zbl 0917.54029 Šlapal, Josef 4 1998 Net spaces in categorical topology. Zbl 0902.54008 Šlapal, Josef 7 1996 A note on general relations. Zbl 0839.04002 Šlapal, Josef 1 1995 A conglomerate of exponential supercategories of the category of finitely generated topological spaces. Zbl 0814.18001 Šlapal, Josef 1 1995 On exponentiation of \(n\)-ary algebras. Zbl 0798.08001 Šlapal, J. 4 1994 Relations and topologies. Zbl 0797.04002 Šlapal, Josef 10 1993 Cardinal arithmetic of general relational systems. Zbl 0797.04001 Šlapal, Josef 4 1993 Exponentiality in concrete categories. Zbl 0793.18004 Šlapal, Josef 2 1993 On embeddings of relational categories into algebraic categories. Zbl 0834.18003 Šlapal, Josef 1 1993 A note on diagonality of algebras. Zbl 0770.08002 Šlapal, Josef 1 1992 Direct arithmetics of relational systems. Zbl 0733.08001 Šlapal, Josef 5 1991 A Cartesian closed topological category of sequential spaces. Zbl 0724.18007 Šlapal, J. 1 1990 A note of F-topologies. Zbl 0712.54001 Šlapal, Josef 3 1989 On the direct power of relational systems. Zbl 0686.08001 Šlapal, Josef 3 1989 Cartesian closedness in categories of relational systems. Zbl 0677.18007 Šlapal, Josef 2 1989 On relations. Zbl 0682.04001 Šlapal, Josef 2 1989 On closure operations induced by binary relations. Zbl 0658.54002 Šlapal, Josef 4 1988 Relations of type \(\alpha\). Zbl 0668.04002 Šlapal, Josef 3 1988 On the axioms preserved by modifications of topologies without axioms. Zbl 0681.54003 Šlapal, Josef 1 1988 all cited Publications top 5 cited Publications all top 5 Cited by 85 Authors 52 Šlapal, Josef 20 Han, Sang-Eon 10 Holgate, David B. 7 Iragi, Minani 5 Razafindrakoto, Ando 3 Castellini, Gabriele 3 Das, Ananga Kumar 3 Dikranjan, Dikran N. 3 Leeratanavalee, Sorasak 3 Richmond, Thomas A. 2 Banakh, Taras Onufrievich 2 Bardyla, Serhii 2 Boonpok, Chawalit 2 Chaisansuk, Nitima 2 Eroglu, Irem 2 Güner, Erdal 2 Gupta, Ria 2 Novák, Vítězslav 2 Novotný, Miroslav 2 Phrommarat, Nitima 2 Yao, Wei 1 Abo-Tabl, E. A. 1 Acharjee, Santanu 1 Allam, Ahmad A. 1 Ameri, Reza 1 Asghari-Larimi, Mohsen 1 Assfaw, Fikreyohans Solomon 1 Bakeir, Mohammad Y. 1 Bhat, Pratibha 1 Darus, Maslina 1 Duckerts-Antoine, Mathieu 1 Dufourd, Jean-François 1 Dydak, Jerzy 1 Estaji, Ali Akbar 1 Fajardo-Rojas, Diego 1 Fajmon, Břetislav 1 Ghosh, Partha Pratim 1 Girish, K. P. 1 Giuli, Eraldo 1 Gran, Marino 1 Haarmann, Jason 1 Haghdadi, Toktam 1 Hardie, Keith A. 1 Hosseini, Seyed Naser 1 Hussain, Saqib 1 Janelidze, Zurab 1 John, Sunil Jacob 1 Jonard-Pérez, Natalia 1 Kang, Jeong Min 1 Khampakdee, Jeeranunt 1 Kovács, Gergely 1 Künzi, Hans-Peter A. 1 Lazaar, Sami 1 Lee, Sik-Yum 1 Li, Changqing 1 Liu, Guilong 1 Lodhi, Saeed 1 Maghsoomi, M. 1 Min, Kyung Chan 1 Mishra, Seema 1 Murcia, Edwin Gonzalo 1 Murphy, Meg P. 1 Na, Il-Kang 1 Nagy, Benedek 1 Peters, Casey S. 1 Pfaltz, John L. 1 Rasheed, Akhter 1 Shah, Syed Ghoos Ali 1 Shakhmatov, Dmitri B. 1 Shir Ali Nasab, Amir Reza 1 Srivastava, Arun Kamar 1 Srivastava, Rekha 1 Staecker, Peter Christopher 1 Sudsanit, Sivaree 1 Tholen, Walter 1 Tiwari, S. P. 1 Tripathy, Binod Chandra 1 Turki, Tarek 1 Vizvári, Béla 1 Wangwe, Lucas 1 Weighill, Thomas 1 Witbooi, Peter Joseph 1 Zhang, Conglei 1 Zhang, Yanlan 1 Zhang, Zhiguo all top 5 Cited in 56 Serials 19 Topology and its Applications 9 Applied Categorical Structures 7 Mathematica Slovaca 6 Quaestiones Mathematicae 5 Czechoslovak Mathematical Journal 5 Filomat 4 Aequationes Mathematicae 3 Discrete Applied Mathematics 3 Theoretical Computer Science 3 Computational and Applied Mathematics 3 Open Mathematics 2 Information Sciences 2 Journal of Computer and System Sciences 2 Acta Mathematica Hungarica 2 Journal of Mathematical Imaging and Vision 2 Theory and Applications of Categories 2 Hacettepe Journal of Mathematics and Statistics 2 Acta Mathematica Universitatis Ostraviensis 2 Journal of Nonlinear Science and Applications 2 Electronic Research Archive 1 Chaos, Solitons and Fractals 1 Algebra Universalis 1 Archiv der Mathematik 1 Collectanea Mathematica 1 Fuzzy Sets and Systems 1 Journal of Algebra 1 Rendiconti del Seminario Matematico della Università di Padova 1 Results in Mathematics 1 Bulletin of the Iranian Mathematical Society 1 Journal of Automated Reasoning 1 International Journal of Approximate Reasoning 1 Applied Mathematics Letters 1 Forum Mathematicum 1 International Journal of Computer Mathematics 1 Topology Proceedings 1 Turkish Journal of Mathematics 1 Annals of Mathematics and Artificial Intelligence 1 Acta Mathematica et Informatica Universitatis Ostraviensis 1 Abstract and Applied Analysis 1 Soft Computing 1 Novi Sad Journal of Mathematics 1 Fundamenta Informaticae 1 Cahiers de Topologie et Géométrie Différentielle Catégoriques 1 Journal of Intelligent and Fuzzy Systems 1 Thai Journal of Mathematics 1 Boletim da Sociedade Paranaense de Matemática. Terceira Série 1 Mediterranean Journal of Mathematics 1 Asian-European Journal of Mathematics 1 Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales. Serie A: Matemáticas. RACSAM 1 TWMS Journal of Pure and Applied Mathematics 1 Journal of Advanced Studies in Topology 1 Journal of Mathematics 1 Cogent Mathematics 1 Categories and General Algebraic Structures with Applications 1 AIMS Mathematics 1 Journal of Algebraic Systems all top 5 Cited in 18 Fields 87 General topology (54-XX) 40 Computer science (68-XX) 37 Category theory; homological algebra (18-XX) 14 General algebraic systems (08-XX) 13 Order, lattices, ordered algebraic structures (06-XX) 11 Combinatorics (05-XX) 10 Mathematical logic and foundations (03-XX) 7 Convex and discrete geometry (52-XX) 7 Algebraic topology (55-XX) 4 Group theory and generalizations (20-XX) 3 Topological groups, Lie groups (22-XX) 2 Manifolds and cell complexes (57-XX) 2 Numerical analysis (65-XX) 1 Associative rings and algebras (16-XX) 1 Functions of a complex variable (30-XX) 1 Operator theory (47-XX) 1 Geometry (51-XX) 1 Differential geometry (53-XX) Citations by Year