<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><DIV>I've found at least a clumsy solution to the problem of putting brackets around an \xymatrix and connecting arrows to another. The problem is that putting arrows within the first \xymatrix caused the left bracket to distort. One solution is to connect arrows inside the first \xymatrix after the brackets are drawn, as below. I'm sure there are better solutions, but since this took me a considerable amount of time to figure out, in case it might be of help to someone else, I'm sending it to the list. </DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>\begin{xy}</DIV><DIV>*!C\xybox{</DIV><DIV>\xymatrix"*"{</DIV><DIV>k_1 & l_1 & 0 & \cdots & 0 & b_1 \\</DIV><DIV>0 & k_2 & l_2 & \ddots & \vdots & \vdots \\</DIV><DIV>\vdots & \ddots & \ddots & \ddots & 0 & b_{N-2} \\</DIV><DIV>0 & \cdots & 0 & *+<1mm>[F-:<10pt>]{k_{N-1}} & l_{N-1} & *+<1mm>[F-:<10pt>]{b_{N-1}} \\</DIV><DIV>l_N & -l_N l_1 & \cdots & *+<1mm>[F-:<10pt>]{-l_N l_1 \cdots l_{N-2}} & k_N & b_N \\</DIV><DIV>}</DIV><DIV>\POS!C,\xybrack,\save "*1,1" . \ar"*2,2", \save "*5,4" . \ar"*4,6", </DIV><DIV>\POS(80,0),</DIV><DIV>\xymatrix{</DIV><DIV>1 \ar@{<-}@/^5mm/["*"dddrrr] & 1 & 1 & 1 & 0 \\ 0 & 1 & -1 & 0 & 0 \\ 0 & 0 & 0 & 1 & 0</DIV><DIV>}</DIV><DIV>}</DIV><DIV>\end{xy}</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Roger</DIV><BR><DIV> <SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><DIV>********************************</DIV><DIV><BR></DIV><DIV>Roger Hart</DIV><DIV>Assistant Professor, Departments of History and Asian Studies</DIV><DIV>University of Texas at Austin</DIV><DIV><BR></DIV><DIV>office: Room 470, Burdine Hall</DIV><DIV>office phone: 512-475-7258</DIV><DIV>department fax: 512-475-7222</DIV><DIV>email: <A href="mailto:rhart@mail.utexas.edu">rhart@mail.utexas.edu</A></DIV><DIV><A href="http://uts.cc.utexas.edu/~rhart">http://uts.cc.utexas.edu/~rhart</A></DIV><DIV><BR></DIV><DIV>*********************************</DIV><BR class="Apple-interchange-newline"></SPAN> </DIV><BR><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">_______________________________________________</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">xy-pic mailing list</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><A href="http://tug.org/mailman/listinfo/xy-pic">http://tug.org/mailman/listinfo/xy-pic</A></DIV> </BODY></HTML>