ovingground.translation.TermRec#plus" group="Ungrouped" fullComment="no" data-isabs="true" visbl="pub"><a id="plus(first:U,second:U):U"></a><a id="plus(U,U):U"></a> <span class="permalink"><a href="../../provingground/translation/TermRec.html#plus(first:U,second:U):U" title="Permalink"><i class="material-icons"></i></a></span> <span class="modifier_kind"><span class="modifier">abstract </span> <span class="kind">def</span></span> <span class="symbol"><span class="name">plus</span><span class="params">(<s