View source for Magari theorem

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The assertion that every [[Variety of universal algebras|variety of universal algebras]] with a non-trivial member contains also a member whose lattice of congruences is $2$-element. Such universal algebras are called congruence-simple or simple [[#References|[a1]]] (see also [[Universal algebra|Universal algebra]]).

====References====
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<TR><TD valign="top">[a1]</TD> <TD valign="top">  S. Burris,   H.P. Sankappanavar,   "A course in universal algebra" , Springer  (1981)  {{ZBL|0478.08001}}</TD></TR>
<TR><TD valign="top">[a2]</TD> <TD valign="top">  R. Magari,   "Una dimonstrazione del fatto che ogni varietà ammette algebre semplici"  ''Ann. Univ. Ferrara Sez. VII (N.S.)'' , '''14'''  (1969)  pp. 1–4  {{DOI|10.1007/BF02896794}}  {{ZBL|0247.08016}}</TD></TR>
<TR><TD valign="top">[a3]</TD> <TD valign="top">  B. Csákány,   "Magari via Malcev"  ''Algebra Universalis'' , '''36'''  (1996)  pp. 421–422  {{DOI|10.1007/BF01236767}} {{ZBL|0901.08008}}</TD></TR>
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