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08A30 Subalgebras, congruence relations (199 articles)

• Guričan, Jaroslav; Ghumashyan, Heghine: Strong endomorphism kernel property for finite Brouwerian semilattices and relative Stone algebras. (English). Mathematica Bohemica, vol. 149 (2024), issue 1, pp. 13-25
• Jun, Jaiung; Mincheva, Kalina; Rowen, Louis: $\mathcal {T}$-semiring pairs. (English). Kybernetika, vol. 58 (2022), issue 5, pp. 733-759
• Zahiri, Saeide; Borumand Saeid, Arsham: An investigation on the $n$-fold IVRL-filters in triangle algebras. (English). Mathematica Bohemica, vol. 145 (2020), issue 1, pp. 75-91
• Halušková, Emília: Some monounary algebras with EKP. (English). Mathematica Bohemica, vol. 145 (2020), issue 4, pp. 401-414
• Halušková, Emília: Strong endomorphism kernel property for monounary algebras. (English). Mathematica Bohemica, vol. 143 (2018), issue 2, pp. 161-171
• Chajda, Ivan; Ledda, Antonio; Paoli, Francesco: Compatible Idempotent Terms in Universal Algebra. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 53 (2014), issue 2, pp. 35-51
• Krajník, Filip; Ploščica, Miroslav: Congruence lattices in varieties with compact intersection property. (English). Czechoslovak Mathematical Journal, vol. 64 (2014), issue 1, pp. 115-132
• Seif, Steve: Congruence lattices of intransitive G-Sets and flat M-Sets. (English). Commentationes Mathematicae Universitatis Carolinae, vol. 54 (2013), issue 4, pp. 459-484
• Ježek, Jaroslav; Kepka, Tomáš; Němec, Petr: Commutative semigroups that are simple over thein endomorphism semirings. (English). Acta Universitatis Carolinae. Mathematica et Physica, vol. 52 (2011), issue 2, pp. 37-50
• Ježek, Jaroslav; Kepka, Tomáš; Němec, Petr: Commutative semigroups with almost transitive endomorphism semirings. (English). Acta Universitatis Carolinae. Mathematica et Physica, vol. 52 (2011), issue 2, pp. 29-32
• Bashir, Robert El; Kepka, Tomáš: Commutative zeropotent semigroups with few invariant congruences. (English). Czechoslovak Mathematical Journal, vol. 58 (2008), issue 4, pp. 865-885
• Kaarli, Kalle; Kuchmei, Vladimir: Order affine completeness of lattices with Boolean congruence lattices. (English). Czechoslovak Mathematical Journal, vol. 57 (2007), issue 4, pp. 1049-1065
• Chajda, Ivan; Halaš, Radomír: Varieties satisfying the triangular scheme need not be congruence distributive. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 46 (2007), issue 1, pp. 19-24
• Čipková, Karla: Ideal extensions of graph algebras. (English). Czechoslovak Mathematical Journal, vol. 56 (2006), issue 3, pp. 933-947
• Novotný, Miroslav: On some constructions of algebraic objects. (English). Czechoslovak Mathematical Journal, vol. 56 (2006), issue 2, pp. 389-402
• Pióro, Konrad: On some unary algebras and their subalgebra lattices. (English). Mathematica Slovaca, vol. 56 (2006), issue 3, pp. 255-273
• Bashir, Robert El; Kepka, Tomáš; Kechlibar, Marian: Commutative semigroups with few fully invariant congruences I. (English). Acta Universitatis Carolinae. Mathematica et Physica, vol. 46 (2005), issue 1, pp. 49-64
• Bashir, Robert El; Kepka, Tomáš; Kechlibar, Marian: Commutative semigroups with few fully invariant congruences II. (English). Acta Universitatis Carolinae. Mathematica et Physica, vol. 46 (2005), issue 1, pp. 65-75
• Chajda, I.; Radelecki, S.: Congruence schemes and their applications. (English). Commentationes Mathematicae Universitatis Carolinae, vol. 46 (2005), issue 1, pp. 1-14
• Chajda, Ivan; Šešelja, Branimir; Tepavčević, Andreja: A note on triangular schemes for weak congruences. (English). Czechoslovak Mathematical Journal, vol. 55 (2005), issue 3, pp. 683-690
• Jedlička, Přemysl: On left distributive left idempotent groupoids. (English). Commentationes Mathematicae Universitatis Carolinae, vol. 46 (2005), issue 1, pp. 15-20
• Chajda, Ivan; Hošková, Šárka: A factorization of quasiorder hypergroups. (English). Commentationes Mathematicae Universitatis Carolinae, vol. 45 (2004), issue 4, pp. 573-581
• Chajda, Ivan; Dorfer, Gerhard; Länger, Helmut: Local versions of some congruence properties in single algebras. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 43 (2004), issue 1, pp. 65-73
• Chajda, Ivan; Länger, Helmut; Mączyński, Maciej: Ring-like structures corresponding to generalized orthomodular lattices. (English). Mathematica Slovaca, vol. 54 (2004), issue 2, pp. 143-150
• Walendziak, Andrzej: Subalgebras and homomorphic images of algebras having the CEP and the WCIP. (English). Czechoslovak Mathematical Journal, vol. 54 (2004), issue 1, pp. 155-160
• Chajda, Ivan; Zedník, Josef: Distributivity and modularity of lattices of quasiorders. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 42 (2003), issue 1, pp. 13-18
• Chajda, Ivan: Generalized deductive systems in subregular varieties. (English). Mathematica Bohemica, vol. 128 (2003), issue 3, pp. 319-324
• Bělohlávek, Radim: Some properties of residuated lattices. (English). Czechoslovak Mathematical Journal, vol. 53 (2003), issue 1, pp. 161-171
• Chajda, Ivan; Halaš, Radomír: Algebraic properties of pre-logics. (English). Mathematica Slovaca, vol. 52 (2002), issue 2, pp. 157-175
• Bělohlávek, Radim: Convex sets in algebras. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 41 (2002), issue 1, pp. 21-33
• Chajda, Ivan: Semiregularity of congruences implies congruence modularity at 0. (English). Czechoslovak Mathematical Journal, vol. 52 (2002), issue 2, pp. 333-336
• Pióro, Konrad: Some properties of the weak subalgebra lattice of a partial algebra of a fixed type. (English). Archivum Mathematicum, vol. 38 (2002), issue 2, pp. 81-94
• Walendziak, Andrzej: Weak congruences of an algebra with the CEP and the WCIP. (English). Czechoslovak Mathematical Journal, vol. 52 (2002), issue 1, pp. 117-127
• Chajda, Ivan: A common generalization of permutability and 0-permutability. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 40 (2001), issue 1, pp. 23-29
• Stanovský, David: Homomorphic images of subdirectly irreducible groupoids. (English). Commentationes Mathematicae Universitatis Carolinae, vol. 42 (2001), issue 3, pp. 443-450
• Pióro, Konrad: On subalgebra lattices of a finite unary algebra. I. (English). Mathematica Bohemica, vol. 126 (2001), issue 1, pp. 161-170
• Pióro, Konrad: On subalgebra lattices of a finite unary algebra. II. (English). Mathematica Bohemica, vol. 126 (2001), issue 1, pp. 171-181
• Bělohlávek, R.: A remark on the ideal extension property. (English). Acta Mathematica et Informatica Universitatis Ostraviensis, vol. 9 (2001), issue 1, pp. 13-14
• Chajda, Ivan; Länger, Helmut: A simple basis of ideal terms of Brouwerian semilattices. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 40 (2001), issue 1, pp. 37-42
• Chajda, Ivan: Varieties which are locally regular and permutable at 0. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 40 (2001), issue 1, pp. 31-35
• Pióro, Konrad: The weak subalgebra lattice of a unary partial algebra of a given infinite unary type. (English). Mathematica Slovaca, vol. 51 (2001), issue 1, pp. 25-44
• Bělohlávek, Radim: A characterization of congruence classes of quasigroups. (English). Mathematica Slovaca, vol. 50 (2000), issue 4, pp. 377-380
• Pióro, Konrad: On connections between hypergraphs and algebras. (English). Archivum Mathematicum, vol. 36 (2000), issue 1, pp. 45-60
• Chajda, Ivan: Uniformity of congruences in coherent varieties. (English). Mathematica Bohemica, vol. 125 (2000), issue 3, pp. 269-273
• Chajda, Ivan; Graczyńska, Ewa: Algebras presented by normal identities. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 38 (1999), issue 1, pp. 49-58
• Chajda, Ivan: Locally coherent algebras. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 38 (1999), issue 1, pp. 43-48
• Dudek, Wiesław Aleksander: On ideals in Hilbert algebras. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 38 (1999), issue 1, pp. 31-34
• Ježek, Jaroslav: Some decidable congruences of free monoids. (English). Czechoslovak Mathematical Journal, vol. 49 (1999), issue 3, pp. 475-480
• Ježek, J.; Markovič, P.; Maróti, M.; McKenzie, R.: The variety generated by tournaments. (English). Acta Universitatis Carolinae. Mathematica et Physica, vol. 40 (1999), issue 1, pp. 21-41
• Walendziak, Andrzej: $(\Cal L$, $\Cal L')$-products of algebras. (English). Mathematica Slovaca, vol. 48 (1998), issue 5, pp. 447-455
• Dudek, Wiesław A.; Zhang, Xiaohong: On ideals and congruences in BCC-algebras. (English). Czechoslovak Mathematical Journal, vol. 48 (1998), issue 1, pp. 21-29
• Chajda, Ivan; Duda, Jaromír: Compact universal relation in varieties with constants. (English). Czechoslovak Mathematical Journal, vol. 47 (1997), issue 1, pp. 173-178
• Chajda, Ivan; Halaš, Radomír; Machala, František: Congruences and ideals in ternary rings. (English). Czechoslovak Mathematical Journal, vol. 47 (1997), issue 1, pp. 163-172
• Chajda, Ivan: The degrees of regularity in varieties. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 36 (1997), issue 1, pp. 27-31
• Vernikov, B. M.: On congruences of $G$-sets. (English). Commentationes Mathematicae Universitatis Carolinae, vol. 38 (1997), issue 3, pp. 603-613
• Barbour, Graham D.; Raftery, James G.: On the degrees of permutability of subregular varieties. (English). Czechoslovak Mathematical Journal, vol. 47 (1997), issue 2, pp. 317-325
• Bělohlávek, Radim; Chajda, Ivan: Polynomially determined congruences in algebras without constants. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 36 (1997), issue 1, pp. 7-14
• Erné, Marcel: Prime Ideal Theorems and systems of finite character. (English). Commentationes Mathematicae Universitatis Carolinae, vol. 38 (1997), issue 3, pp. 513-536
• Chajda, Ivan: Rees ideal algebras. (English). Mathematica Bohemica, vol. 122 (1997), issue 2, pp. 125-130
• Zelinka, Bohdan: Atomary tolerances on finite algebras. (English). Mathematica Bohemica, vol. 121 (1996), issue 1, pp. 35-39
• Chajda, Ivan: Congruence semimodularity of conservative groupoids. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 35 (1996), issue 1, pp. 43-45
• Halaš, Radomír: Congruences and ideals on left divisible involutory groupoids. (English). Mathematica Bohemica, vol. 121 (1996), issue 3, pp. 269-272
• Walendziak, Andrzej: Existence and uniqueness of $(L,\varphi)$-representations of algebras. (English). Czechoslovak Mathematical Journal, vol. 46 (1996), issue 1, pp. 35-46
• Chajda, I.; Rosenberg, I. G.: Ideals and congruence kernels of algebras. (English). Czechoslovak Mathematical Journal, vol. 46 (1996), issue 4, pp. 733-744
• Pondělíček, Bedřich: Inverse semirings and their lattice of congruences. (English). Czechoslovak Mathematical Journal, vol. 46 (1996), issue 3, pp. 513-522
• Pilitowska, Agata; Romanowska, Anna; Roszkowska-Lech, Barbara: Products of mode varieties and algebras of subalgebras. (English). Mathematica Slovaca, vol. 46 (1996), issue 5, pp. 497-514
• Chajda, Ivan: Regularity and permutability via transferability of tolerances. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 35 (1996), issue 1, pp. 39-42
• Chajda, Ivan; Emanovský, Petr: $\Sigma$-Hamiltonian and $\Sigma$-regular algebraic structures. (English). Mathematica Bohemica, vol. 121 (1996), issue 2, pp. 177-182
• Chajda, Ivan: Tolerances on $q$-lattices. (English). Czechoslovak Mathematical Journal, vol. 46 (1996), issue 1, pp. 21-28
• Chajda, Ivan: The Csákány theory of regularity for finite algebras. (English). Mathematica Slovaca, vol. 45 (1995), issue 1, pp. 39-43
• Czédli, Gábor: Diamond identities for relative congruences. (English). Archivum Mathematicum, vol. 31 (1995), issue 1, pp. 65-74
• Pondělíček, Bedřich: A note on tolerance lattices of algebras with restricted similarity type. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 34 (1995), issue 1, pp. 147-149
• Chajda, Ivan: Semilattices of finite arithmetical algebras. (English). Czechoslovak Mathematical Journal, vol. 45 (1995), issue 4, pp. 659-662
• Chajda, Ivan: Some modifications of the congruence extension property. (English). Mathematica Slovaca, vol. 45 (1995), issue 3, pp. 251-254
• Chajda, Ivan: Tolerance lattice of algebras with restricted similarity type. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 34 (1995), issue 1, pp. 59-62
• Chajda, Ivan: Algebras with $n$-transferable tolerances. (English). Mathematica Bohemica, vol. 119 (1994), issue 2, pp. 137-142
• Chajda, Ivan: Characterizing tolerance trivial finite algebras. (English). Archivum Mathematicum, vol. 30 (1994), issue 3, pp. 165-169
• Pondělíček, Bedřich: On generalized conditionally commutative semigroups. (English). Mathematica Slovaca, vol. 44 (1994), issue 3, pp. 359-364
• Pinus, Alexander G.; Michailov, M. M.: On the approximation of the Boolean powers by Cartesian powers. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 33 (1994), issue 1, pp. 105-108
• Chajda, Ivan: Principal tolerances on lattices. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 33 (1994), issue 1, pp. 17-22
• Abrhan, Imrich; Satko, Ladislav: $r$-systems of unary algebras. II: Maximal and minimal subalgebras of the direct products of unary algebras. (English). Mathematica Slovaca, vol. 44 (1994), issue 1, pp. 69-83
• Zelinka, Bohdan: Representation of undirected graphs by anticommutative conservative groupoids. (English). Mathematica Bohemica, vol. 119 (1994), issue 3, pp. 231-237
• Walendziak, Andrzej: $(L,\varphi)$-representations of algebras. (English). Archivum Mathematicum, vol. 29 (1993), issue 2, pp. 135-143
• Chajda, Ivan: Regular lattices. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 32 (1993), issue 1, pp. 17-20
• Duda, Jaromír: Subcoherent algebras. (English). Czechoslovak Mathematical Journal, vol. 43 (1993), issue 2, pp. 281-284
• Chajda, Ivan: Characterizations of Hamiltonian algebras. (English). Czechoslovak Mathematical Journal, vol. 42 (1992), issue 3, pp. 487-489
• Duda, Jaromír: Coherence and weak coherence in the square of algebras. (English). Czechoslovak Mathematical Journal, vol. 42 (1992), issue 4, pp. 613-618
• Rosenberg, Ivo G.; Sturm, Teo: Congruence relations on finitary models. (English). Czechoslovak Mathematical Journal, vol. 42 (1992), issue 3, pp. 461-470
• Duda, Jaromír: Congruence restrictions on axes. (English). Mathematica Bohemica, vol. 117 (1992), issue 3, pp. 251-258
• Duda, Jaromír: Factorable congruences and factorable congruence blocks on powers of a finite algebra. (English). Czechoslovak Mathematical Journal, vol. 42 (1992), issue 1, pp. 89-93
• Chajda, Ivan: A note on varieties with distributive subalgebra lattices. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 31 (1992), issue 1, pp. 25-28
• Niederle, Josef: On frame congruences generated by frame tolerances. (English). Archivum Mathematicum, vol. 28 (1992), issue 1, pp. 77-81
• Jordens, Olav: On modularity in lattices of congruences on ordered sets. (English). Czechoslovak Mathematical Journal, vol. 42 (1992), issue 3, pp. 451-460
• Pondělíček, Bedřich: Subalgebra modular, distributive and boolean varieties of semigroups. (English). Czechoslovak Mathematical Journal, vol. 42 (1992), issue 4, pp. 757-764
• Raftery, J. G.; Sturm, T.: Tolerance numbers, congruence $n$-permutability and BCK-algebras. (English). Czechoslovak Mathematical Journal, vol. 42 (1992), issue 4, pp. 727-740
• Zelinka, Bohdan: Tolerances on poset algebras. (English). Mathematica Bohemica, vol. 117 (1992), issue 1, pp. 93-97
• Duda, Jaromír: Tolerances on powers of a finite algebra. (English). Mathematica Bohemica, vol. 117 (1992), issue 3, pp. 299-304
• Radelecki, Sándor: Compatible tolerances on groupoids. (English). Czechoslovak Mathematical Journal, vol. 41 (1991), issue 3, pp. 436-445
• Duda, Jaromír: Conditions for factorable relations. (English). Czechoslovak Mathematical Journal, vol. 41 (1991), issue 1, pp. 131-134
• Adams, Michael E.; Beazer, Rod: Congruence properties of distributive double $p$-algebras. (English). Czechoslovak Mathematical Journal, vol. 41 (1991), issue 2, pp. 216-231
• Adams, Michael E.; Beazer, Rod: Double $p$-algebras with Stone congruence lattices. (English). Czechoslovak Mathematical Journal, vol. 41 (1991), issue 3, pp. 395-404
• Chajda, Ivan: Every at most four element algebra has a Mal'cev theory for permutability. (English). Mathematica Slovaca, vol. 41 (1991), issue 1, pp. 35-39
• Pondělíček, Bedřich: On permutability in semigroup varieties. (English). Mathematica Bohemica, vol. 116 (1991), issue 4, pp. 396-400
• Chajda, Ivan: Permutability of congruences in varieties with idempotent operations. (English). Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica, vol. 30 (1991), issue 1, pp. 33-37
• Duda, Jaromír: Relation products of congruences and factor congruences. (English). Czechoslovak Mathematical Journal, vol. 41 (1991), issue 1, pp. 155-159
• Niederle, Josef: Tolerances of frames. (English). Archivum Mathematicum, vol. 27 (1991), issue 1, pp. 79-84
• Chajda, Ivan: Weak coherence of congruences. (English). Czechoslovak Mathematical Journal, vol. 41 (1991), issue 1, pp. 149-154
• Chajda, Ivan: On the existence of non-trivial tolerances in permutable algebras. (English). Czechoslovak Mathematical Journal, vol. 40 (1990), issue 4, pp. 598-600
• Pondělíček, Bedřich: Tolerance modular varieties of semigroups. (English). Czechoslovak Mathematical Journal, vol. 40 (1990), issue 3, pp. 441-452
• Niederle, Josef: Transitivity of principal tolerances is not a Mal'cev property. (English). Czechoslovak Mathematical Journal, vol. 40 (1990), issue 4, pp. 563-565
• Bartol, Wiktor: Weak subalgebra lattices. (English). Commentationes Mathematicae Universitatis Carolinae, vol. 31 (1990), issue 3, pp. 405-410
• Bartol, Wiktor: Weak subalgebra lattices of monounary partial algebras. (English). Commentationes Mathematicae Universitatis Carolinae, vol. 31 (1990), issue 3, pp. 411-414
• Chajda, Ivan; Pondělíček, Bedřich: Algebras with tolerance extension property in 0. (English). Czechoslovak Mathematical Journal, vol. 39 (1989), issue 1, pp. 142-146
• Duda, Jaromír: Coherence implies congruence-regularity (a local version). (English). Commentationes Mathematicae Universitatis Carolinae, vol. 30 (1989), issue 1, pp. 191
• Duda, Jaromír: Coherence in varieties of algebras. (English). Czechoslovak Mathematical Journal, vol. 39 (1989), issue 4, pp. 711-716
• Ševečková, Jitka; Šik, František: Complete permutability of partitions in a set. I. (English). Archivum Mathematicum, vol. 25 (1989), issue 1, pp. 95-102
• Niederle, Josef: Conditions for transitive principal tolerances. (English). Czechoslovak Mathematical Journal, vol. 39 (1989), issue 2, pp. 380-381
• Duda, Jaromír: Mal'cev conditions for directly decomposable compatible relations. (English). Czechoslovak Mathematical Journal, vol. 39 (1989), issue 4, pp. 674-680
• Chajda, Ivan: On Grätzer's problem of binary 1-step congruence schemes. (English). Czechoslovak Mathematical Journal, vol. 39 (1989), issue 3, pp. 470-476
• Chajda, Ivan: Principal tolerances on lattices. (English). Czechoslovak Mathematical Journal, vol. 39 (1989), issue 1, pp. 176-180
• Grätzer, G.; Wenzel, G. H.: Tolerances, covering systems, and the axiom of choice. (English). Archivum Mathematicum, vol. 25 (1989), issue 1, pp. 27-34
• Chajda, Ivan; Duda, Jaromír: Varieties satisfying ideal equalities. (English). Mathematica Slovaca, vol. 39 (1989), issue 1, pp. 55-63
• Chajda, Ivan: Algebras whose principal congruences form a sublattice of the congruence lattice. (English). Czechoslovak Mathematical Journal, vol. 38 (1988), issue 4, pp. 585-588
• Pondělíček, Bedřich: Direct decomposability of tolerances and congruences on semigroups. (English). Czechoslovak Mathematical Journal, vol. 38 (1988), issue 4, pp. 701-704
• Chajda, Ivan: The egg-box property of congruences. (English). Mathematica Slovaca, vol. 38 (1988), issue 3, pp. 243-247
• Chajda, Ivan; Zelinka, Bohdan: Tolerances and congruences on implication algebras. (English). Czechoslovak Mathematical Journal, vol. 38 (1988), issue 2, pp. 207-217
• Chajda, Ivan: Tolerances in congruence permutable algebras. (English). Czechoslovak Mathematical Journal, vol. 38 (1988), issue 2, pp. 218-225
• Zelinka, Bohdan: Tolerances of polyunary algebras. (English). Archivum Mathematicum, vol. 24 (1988), issue 1, pp. 1-4
• Vrancken-Mawet, L.: The 0-distributivity in the class of subalgebra lattices of Heyting algebras and closure algebras. (English). Commentationes Mathematicae Universitatis Carolinae, vol. 28 (1987), issue 2, pp. 387-396
• Chajda, Ivan: Algebras with principal tolerances. (English). Mathematica Slovaca, vol. 37 (1987), issue 2, pp. 169-172
• Chajda, Ivan: Directly decomposable congruences in varieties with nullary operations. (English). Mathematica Slovaca, vol. 37 (1987), issue 1, pp. 31-35
• Schweigert, Dietmar; Szymańska, Magdalena: On central relations of complete lattices. (English). Czechoslovak Mathematical Journal, vol. 37 (1987), issue 1, pp. 70-74
• Chajda, Ivan: On the one principal congruence identity. (English). Archivum Mathematicum, vol. 23 (1987), issue 4, pp. 187-190
• Zelinka, Bohdan: Tolerances on graph algebras. (English). Czechoslovak Mathematical Journal, vol. 37 (1987), issue 2, pp. 313-317
• Chajda, Ivan: Congruence distributivity in varieties with constants. (English). Archivum Mathematicum, vol. 22 (1986), issue 3, pp. 121-124
• Duda, Jaromír: Congruences on products in varieties satisfying the CEP. (English). Mathematica Slovaca, vol. 36 (1986), issue 2, pp. 171-177
• Loganathan, M.: On tolerance relations. (English). Czechoslovak Mathematical Journal, vol. 36 (1986), issue 4, pp. 662-667
• Tůma, Jiří: Some finite congruence lattices, I. (English). Czechoslovak Mathematical Journal, vol. 36 (1986), issue 2, pp. 298-330
• Duda, Jaromír: Varieties having directly decomposable congruence classes. (English). Časopis pro pěstování matematiky, vol. 111 (1986), issue 4, pp. 394-403
• Chajda, Ivan: Coherence in dual discriminator varieties. (English). Mathematica Slovaca, vol. 35 (1985), issue 2, pp. 155-159
• Ramana Murty, P.V.; Raman, V.: Permutability of distributive congruence relations in a joint semilattice directed below. (English). Mathematica Slovaca, vol. 35 (1985), issue 1, pp. 43-49
• Tůma, Jiří: A simple geometric proof of a theorem on $M_n$. (English). Commentationes Mathematicae Universitatis Carolinae, vol. 26 (1985), issue 2, pp. 233-239
• Chajda, Ivan: Varieties with tolerance and congruence extension property. (English). Archivum Mathematicum, vol. 21 (1985), issue 1, pp. 5-12
• Länger, Helmut: C-S-maximal superassociative systems. II. (English). Mathematica Slovaca, vol. 34 (1984), issue 1, pp. 89-95
• Kumaresan, K.: A note on idempotent separating congruences on a regular semigroup. (English). Czechoslovak Mathematical Journal, vol. 34 (1984), issue 2, pp. 315-318
• Kumaresan, K.: A note on the strongly compatible tolerances on an arbitrary semigroup. (English). Czechoslovak Mathematical Journal, vol. 34 (1984), issue 2, pp. 319-321
• Zelinka, Bohdan: Tolerances on monounary algebras. (English). Czechoslovak Mathematical Journal, vol. 34 (1984), issue 2, pp. 298-304
• Chajda, Ivan: Transferable principal congruences and regular algebras. (English). Mathematica Slovaca, vol. 34 (1984), issue 1, pp. 97-102
• Bandelt, Hans-Jürgen: Tolerante Catalanzahlen. (German) [Tolerant Catalan numbers]. Archivum Mathematicum, vol. 19 (1983), issue 3, pp. 113-115
• Niederle, Josef: Conditions for trivial principal tolerances. (English). Archivum Mathematicum, vol. 19 (1983), issue 3, pp. 145-152
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