<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Heeffer, Albrecht</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">The Abbacus Tradition: the Missing Link between Arabic and Early Symbolic Algebra?</style></title></titles><dates><year><style  face="normal" font="default" size="100%">2009</style></year></dates><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Abbaco algebra is a coherent tradition of arithmetical and algebraic problem solving, mostly based in the merchant cities of fourteenth and fifteenth-century Italy. This period is roughly situated between two impor- tant works dealing with algebra: the &lt;em&gt;Liber Abbaci&lt;/em&gt; by Fibonacci (1202) [5] and the &lt;em&gt;Summa di Arithmetica et Geometria&lt;/em&gt; by Luca Pacioli (1492) [20]. Such continuous tradition of mathematical practice was hardly known be- fore the first transcriptions of extant manuscripts by Gino Arrighi from the 1960's (most notably [1], [2], [3] and [4]) and the ground-breaking work by Warren van Egmond [28]. After some decades of manuscript study and the recent assessment of Jens Høyrup [10] we now have a bet- ter understanding of this tradition. Here we provide an overview of the basic characteristics of the abbaco tradition and discuss the role it played towards the new symbolic algebra as it emerged in sixteenth-century Europe.&lt;/p&gt;</style></abstract></record></records></xml>