<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><DIV>When I sent this first, I forgot to include another newcommand in the tex source (\fof).</DIV><DIV><BR class="khtml-block-placeholder"></DIV>I am trying to align four long lines of formula, where the item in the first line being aligned is inside a set of delimiters. I tried breaking this up, using \right. and \left . where appropriate (and using size commands to make sure the size of the delimiters is correct, but somehow amstex is looking for a closing brace: I can't find where the "opening" brace that prompts it to do so is located.<DIV><BR class="khtml-block-placeholder"></DIV><DIV>Here is my tex source; I include definitions of my commands being used</DIV><DIV>*****************************************************************************************************</DIV><DIV>\newcommand{\pddat}[3]{\frac{\partial#1}{\partial#2}\left(#3\right)}</DIV><DIV>\newcommand{\delx}{\triangle x}</DIV><DIV>\newcommand{\dely}{\triangle y}</DIV><DIV>\newcommand{\fof}[1]{f\left(#1\right)}</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>\begin{equation*}</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>\begin{split}</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>\fof{x+\delx,y+\dely}-\biggl(\fof{x,y}\right.</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>&+\left.\pddat{f}{x}{x,y}\delx</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>+\pddat{f}{y}{x,y}\dely\right)\\</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>=\biggl(\fof{x+\delx,y+\dely}-\fof{x,y}\biggr)</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>&-\left(\pddat{f}{x}{x,y}\delx</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>+\pddat{f}{y}{x,y}\dely\right)\\</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>=\left(\pddat{f}{x}{x+\delts{1},y+\dely}\delx</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>+\pddat{f}{y}{x,y+\delts{2}}\dely\right)</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>&-\left(\pddat{f}{x}{x,y}\delx</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>+\pddat{f}{y}{x,y}\dely\right)\\</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>=\left(\pddat{f}{x}{x+\delts{1},y+\dely}-\pddat{f}{x}{x,y}\right)\delx</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>&+\left(\pddat{f}{y}{x,y+\delts{2}}-\pddat{f}{y}{x,y}\right)\dely.</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>\end{split}</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>\end{equation*}</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>****************************************************************************************************</DIV><DIV>and here is the error message:</DIV><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; "><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>! Missing } inserted.</DIV><DIV><inserted text> </DIV><DIV> }</DIV><DIV>l.243 <SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>\end{split}</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; ">******************************************<BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; ">in TexShop, when I then go into nonstop mode ("r") the formula compiles fine, looking as I intended. If I break the stuff into two separate equation*/split environments, with the first set the first two lines (ie, break after the second \\), then the same occurs, but if I then comment out the first of these two, I get no error. Clearly the problem is in the first "line", but I can't figure it out.</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><BR class="khtml-block-placeholder"></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; ">Any ideas, on a cause and/or a fix?</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><BR class="khtml-block-placeholder"></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Zbigniew Nitecki</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Department of Mathematics</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Tufts University</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Medford, MA 02155</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">telephones:</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Office<SPAN class="Apple-converted-space"><SPAN class="Apple-converted-tab"> <SPAN class="Apple-converted-space"> </SPAN></SPAN></SPAN>(617)627-3843</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Dept.<SPAN class="Apple-converted-space"><SPAN class="Apple-converted-tab"> <SPAN class="Apple-converted-space"> </SPAN></SPAN></SPAN>(617)627-3234</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Dept. fax<SPAN class="Apple-converted-space"><SPAN class="Apple-converted-tab"> <SPAN class="Apple-converted-space"> </SPAN></SPAN></SPAN>(617)627-3966</FONT></DIV><BR class="Apple-interchange-newline"></SPAN></SPAN> </DIV><BR></DIV></BODY></HTML>