diff --git a/src/commands/math.ts b/src/commands/math.ts
index 953b56f2f..fbf719d87 100644
--- a/src/commands/math.ts
+++ b/src/commands/math.ts
@@ -617,8 +617,23 @@ class MathBlock extends MathElement {
   }
   chToCmd(ch: string, options: CursorOptions) {
     var cons;
-    // exclude f because it gets a dedicated command with more spacing
-    if (ch.match(/^[a-eg-zA-Z]$/)) return new Letter(ch);
+    // extract customCharacters early so we can easily default it to 'f'
+    var customCharacters = options?.customCharacters ?? 'f';
+    if (
+      customCharacters.indexOf(ch) >= 0 &&
+      (cons = (CharCmds as CharCmdsAny)[ch] || (LatexCmds as LatexCmdsAny)[ch])
+    ) {
+      if (cons.constructor) {
+        return new cons(ch);
+      } else {
+        return cons(ch);
+      }
+    } else if (
+      // the patch to exclude 'f' from this regex is no longer needed since we
+      // usecustomCharacters
+      ch.match(/^[a-zA-Z]$/)
+    )
+      return new Letter(ch);
     else if (/^\d$/.test(ch)) return new Digit(ch);
     else if (options && options.typingSlashWritesDivisionSymbol && ch === '/')
       return (LatexCmds as LatexCmdsSingleCharBuilder)['÷'](ch);
diff --git a/src/commands/math/advancedSymbols.ts b/src/commands/math/advancedSymbols.ts
index d99465b66..76b802f29 100644
--- a/src/commands/math/advancedSymbols.ts
+++ b/src/commands/math/advancedSymbols.ts
@@ -644,12 +644,12 @@ LatexCmds.closecurlybrace = LatexCmds.rbrace = bindVanillaSymbol(
   '}',
   'right brace'
 );
-LatexCmds.lbrack = bindVanillaSymbol('[', 'left bracket');
-LatexCmds.rbrack = bindVanillaSymbol(']', 'right bracket');
+LatexCmds.lbrack = bindVanillaSymbol('[', '[', 'left bracket');
+LatexCmds.rbrack = bindVanillaSymbol(']', ']', 'right bracket');
 
 //various symbols
-LatexCmds.slash = bindVanillaSymbol('/', 'slash');
-LatexCmds.vert = bindVanillaSymbol('|', 'vertical bar');
+LatexCmds.slash = bindVanillaSymbol('/', '/', 'slash');
+LatexCmds.vert = bindVanillaSymbol('|', '|', 'vertical bar');
 LatexCmds.perp = LatexCmds.perpendicular = bindVanillaSymbol(
   '\\perp ',
   '⊥',
diff --git a/src/commands/math/basicSymbols.ts b/src/commands/math/basicSymbols.ts
index a41afbc05..d59f68aaf 100644
--- a/src/commands/math/basicSymbols.ts
+++ b/src/commands/math/basicSymbols.ts
@@ -647,7 +647,7 @@ function defaultAutoOpNames() {
     _maxLength: 9,
   };
   var mostOps = (
-    'arg deg det dim exp gcd hom inf ker lg lim ln log max min sup' +
+    'arg deg det dim exp gcd hom inf ker lg ln log max min sup' +
     ' limsup liminf injlim projlim Pr'
   ).split(' ');
   for (var i = 0; i < mostOps.length; i += 1) {
diff --git a/src/commands/math/commands.ts b/src/commands/math/commands.ts
index b8a672a64..ba147259f 100644
--- a/src/commands/math/commands.ts
+++ b/src/commands/math/commands.ts
@@ -953,7 +953,9 @@ var LiveFraction =
                   leftward._groupingClass === 'mq-ellipsis-end') ||
                 leftward instanceof (LatexCmds.text || noop) ||
                 leftward instanceof SummationNotation ||
+                leftward instanceof Limit ||
                 leftward.ctrlSeq === '\\ ' ||
+                leftward.ctrlSeq === '&' ||
                 /^[,;:]$/.test(leftward.ctrlSeq as string)
               ) //lookbehind for operator
             )
@@ -1616,7 +1618,9 @@ LatexCmds.left = class extends MathCommand {
     var optWhitespace = Parser.optWhitespace;
 
     return optWhitespace
-      .then(regex(/^(?:[([|]|\\\{|\\langle(?![a-zA-Z])|\\lVert(?![a-zA-Z]))/))
+      .then(
+        regex(/^(?:[([|]|\\\{|\\(?:lfloor|lceil|langle|lVert)(?![a-zA-z]))/)
+      )
       .then(function (ctrlSeq) {
         var open = ctrlSeq.replace(/^\\/, '');
         if (ctrlSeq == '\\langle') {
@@ -1630,9 +1634,7 @@ LatexCmds.left = class extends MathCommand {
         return latexMathParser.then(function (block) {
           return string('\\right')
             .skip(optWhitespace)
-            .then(
-              regex(/^(?:[\])|]|\\\}|\\rangle(?![a-zA-Z])|\\rVert(?![a-zA-Z]))/)
-            )
+            .then(regex(/^(?:[\])|]|\\\}|\\[a-zA-z]+)/))
             .map(function (end) {
               var close = end.replace(/^\\/, '');
               if (end == '\\rangle') {
@@ -1869,3 +1871,40 @@ class EmbedNode extends MQSymbol {
   }
 }
 LatexCmds.embed = EmbedNode;
+class Limit extends MathCommand {
+  constructor(ctrlSeq?: string, domView?: DOMView, textTemplate?: string[]) {
+    super(ctrlSeq, domView, textTemplate);
+    this.ctrlSeq = '\\lim';
+    this.domView = new DOMView(1, function (blocks) {
+      return h('span', { class: 'mq-limit mq-non-leaf' }, [
+        h('span', { class: 'mq-limit-label' }, [h.text('lim')]),
+        h.block('span', { class: 'mq-limit-sub mq-non-leaf' }, blocks[0]),
+      ]);
+    });
+    this.textTemplate = ['lim(', ')'];
+    this.mathspeakTemplate = ['Limit', 'EndLimit'];
+  }
+
+  override latexRecursive(ctx: LatexContext) {
+    this.checkCursorContextOpen(ctx);
+    ctx.latex += '\\lim_{';
+    this.getEnd(L).latexRecursive(ctx);
+    ctx.latex += '}';
+    this.checkCursorContextClose(ctx);
+  }
+
+  override parser() {
+    return Parser.string('_')
+      .then(function () {
+        return latexMathParser;
+      })
+      .map(function (block) {
+        const limit = new Limit('\\lim', undefined!, undefined!);
+        limit.blocks = [block];
+        block.adopt(limit, 0, 0);
+        return limit;
+      })
+      .or(super.parser());
+  }
+}
+LatexCmds.limit = LatexCmds.lim = Limit;
diff --git a/src/css/math.less b/src/css/math.less
index 42845dac4..1f6b7ae56 100644
--- a/src/css/math.less
+++ b/src/css/math.less
@@ -1,12 +1,13 @@
 // look here to see the digit layout strategy:
 // https://www.desmos.com/calculator/ctvh9utz0t
-@digit-separator: .11em;
-@expand-margin: .009em;
-@contract-margin: -.01em;
-@ellipsis-separator: .14em;
+@digit-separator: 0.11em;
+@expand-margin: 0.009em;
+@contract-margin: -0.01em;
+@ellipsis-separator: 0.14em;
 @ellipsis-internal-sep: 0.009em;
 
-.mq-root-block, .mq-math-mode .mq-root-block {
+.mq-root-block,
+.mq-math-mode .mq-root-block {
   .inline-block;
   width: 100%;
   padding: 2px;
@@ -30,7 +31,8 @@
     margin-right: @contract-margin;
   }
 
-  .mq-group-leading-1, .mq-group-leading-2 {
+  .mq-group-leading-1,
+  .mq-group-leading-2 {
     margin-left: 0;
     margin-right: @contract-margin;
   }
@@ -41,7 +43,11 @@
   }
 
   &.mq-suppress-grouping {
-    .mq-group-start, .mq-group-other, .mq-group-leading-1, .mq-group-leading-2, .mq-group-leading-3 {
+    .mq-group-start,
+    .mq-group-other,
+    .mq-group-leading-1,
+    .mq-group-leading-2,
+    .mq-group-leading-3 {
       margin-left: @expand-margin;
       margin-right: @expand-margin;
     }
@@ -71,14 +77,17 @@
   line-height: 1;
 
   .inline-block;
-  .mq-non-leaf, .mq-scaled {
+  .mq-non-leaf,
+  .mq-scaled {
     .inline-block;
   }
 
   // TODO: dasherize non-symbola
-  var, .mq-text-mode, .mq-nonSymbola {
+  var,
+  .mq-text-mode,
+  .mq-nonSymbola {
     font-family: @times;
-    line-height: .9;
+    line-height: 0.9;
   }
 
   svg {
@@ -88,7 +97,7 @@
     fill: currentColor;
 
     // the svg symbols fill their container
-    position:absolute;
+    position: absolute;
     top: 0;
     left: 0;
     width: 100%;
@@ -107,12 +116,12 @@
 
   // TODO: what's the difference between these?
   .mq-empty {
-    background: rgba(0,0,0,.2);
+    background: rgba(0, 0, 0, 0.2);
     &.mq-root-block {
       background: transparent;
     }
     &.mq-quiet-delimiter {
-      background: transparent
+      background: transparent;
     }
   }
 
@@ -126,9 +135,9 @@
   }
 
   .mq-text-mode.mq-hasCursor {
-    box-shadow: inset darkgray 0 .1em .2em;
-    padding: 0 .1em;
-    margin: 0 -.1em;
+    box-shadow: inset darkgray 0 0.1em 0.2em;
+    padding: 0 0.1em;
+    margin: 0 -0.1em;
 
     min-width: 1ex;
   }
@@ -143,11 +152,14 @@
   }
 
   // TODO [Han]: Why do we have to special-case .font?
-  b, b.mq-font {
+  b,
+  b.mq-font {
     font-weight: bolder;
   }
 
-  var, i, i.mq-font {
+  var,
+  i,
+  i.mq-font {
     font-style: italic;
   }
 
@@ -167,21 +179,21 @@
   .mq-int {
     > big {
       display: inline-block;
-      .transform(scaleX(.7));
-      vertical-align: -.16em;
+      .transform(scaleX(0.7));
+      vertical-align: -0.16em;
     }
 
     > .mq-supsub {
       font-size: 80%;
       vertical-align: -1.1em;
-      padding-right: .2em;
+      padding-right: 0.2em;
 
       > .mq-sup > .mq-sup-inner {
         vertical-align: 1.3em;
       }
 
       > .mq-sub {
-        margin-left: -.35em;
+        margin-left: -0.35em;
       }
     }
   }
@@ -227,10 +239,10 @@
   .mq-supsub {
     text-align: left;
     font-size: 90%;
-    vertical-align: -.5em;
+    vertical-align: -0.5em;
 
     &.mq-sup-only {
-      vertical-align: .5em;
+      vertical-align: 0.5em;
 
       & > .mq-sup {
         display: inline-block;
@@ -248,7 +260,7 @@
     }
 
     .mq-binary-operator {
-      padding: 0 .1em;
+      padding: 0 0.1em;
     }
 
     // special styles for fractions
@@ -261,19 +273,22 @@
   sup.mq-nthroot {
     font-size: 80%;
     vertical-align: 0.8em;
-    margin-right: -.6em;
-    margin-left: .2em;
-    min-width: .5em;
+    margin-right: -0.6em;
+    margin-left: 0.2em;
+    min-width: 0.5em;
   }
 
   ////
   // parentheses
-  .mq-ghost svg { opacity: .2 }
+  .mq-ghost svg {
+    opacity: 0.2;
+  }
   .mq-bracket-middle {
-    margin-top: .1em;
-    margin-bottom: .1em;
+    margin-top: 0.1em;
+    margin-bottom: 0.1em;
   }
-  .mq-bracket-l, .mq-bracket-r {
+  .mq-bracket-l,
+  .mq-bracket-r {
     position: absolute;
     top: 0;
     bottom: 2px;
@@ -282,7 +297,7 @@
     left: 0;
   }
   .mq-bracket-r {
-    right:0;
+    right: 0;
   }
   .mq-bracket-container {
     position: relative;
@@ -301,15 +316,16 @@
   // non-italicized operator names
   // like \sin, \cos, \ln, etc.
   .mq-operator-name {
-    font-family: Symbola, "Times New Roman", serif;
-    line-height: .9;
+    font-family: Symbola, 'Times New Roman', serif;
+    line-height: 0.9;
     font-style: normal;
   }
   var.mq-operator-name.mq-first {
-    padding-left: .2em;
+    padding-left: 0.2em;
   }
-  var.mq-operator-name.mq-last, .mq-supsub.mq-after-operator-name {
-    padding-right: .2em;
+  var.mq-operator-name.mq-last,
+  .mq-supsub.mq-after-operator-name {
+    padding-right: 0.2em;
   }
 
   ////
@@ -321,22 +337,29 @@
   .mq-fraction {
     font-size: 90%;
     text-align: center;
-    vertical-align: -.4em;
-    padding: 0 .2em;
+    vertical-align: -0.4em;
+    padding: 0 0.2em;
   }
 
   // Firefox 2 (and older?) only
   // because display:inline-block is FUBAR in Gecko < 1.9.0
-  .mq-fraction, .mq-large-operator, x:-moz-any-link {
+  .mq-fraction,
+  .mq-large-operator,
+  x:-moz-any-link {
     display: -moz-groupbox;
   }
 
   // Firefox 3+ (Gecko 1.9.0+)
-  .mq-fraction, .mq-large-operator, x:-moz-any-link, x:default {
+  .mq-fraction,
+  .mq-large-operator,
+  x:-moz-any-link,
+  x:default {
     display: inline-block;
   }
 
-  .mq-numerator, .mq-denominator, .mq-dot-recurring {
+  .mq-numerator,
+  .mq-denominator,
+  .mq-dot-recurring {
     display: block;
   }
 
@@ -374,16 +397,16 @@
     border-top: 1px solid;
     margin-top: 1px;
     margin-left: 0.9em;
-    padding-left: .15em;
-    padding-right: .2em;
-    margin-right: .1em;
+    padding-left: 0.15em;
+    padding-right: 0.2em;
+    margin-right: 0.1em;
     padding-top: 1px;
   }
 
   .mq-diacritic-above {
     display: block;
     text-align: center;
-    line-height: .4em;
+    line-height: 0.4em;
   }
 
   .mq-diacritic-stem {
@@ -394,8 +417,8 @@
   .mq-hat-prefix {
     display: block;
     text-align: center;
-    line-height: .95em;
-    margin-bottom: -.7em;
+    line-height: 0.95em;
+    margin-bottom: -0.7em;
     transform: scaleX(1.5);
     -moz-transform: scaleX(1.5);
     -o-transform: scaleX(1.5);
@@ -407,14 +430,17 @@
   }
 
   .mq-large-operator {
-    vertical-align: -.2em;
-    padding: .2em;
+    vertical-align: -0.2em;
+    padding: 0.2em;
     text-align: center;
 
-    .mq-from, big, .mq-to  {
+    .mq-from,
+    big,
+    .mq-to {
       display: block;
     }
-    .mq-from, .mq-to  {
+    .mq-from,
+    .mq-to {
       font-size: 80%;
     }
     .mq-from {
@@ -423,26 +449,26 @@
     }
   }
 
-
-  &, .mq-editable-field {
+  &,
+  .mq-editable-field {
     cursor: text;
     font-family: @symbola;
   }
 
   .mq-overarc {
     border-top: 1px solid black;
-    -webkit-border-top-right-radius: 50% .3em;
-    -moz-border-radius-topright: 50% .3em;
-    border-top-right-radius: 50% .3em;
-    -webkit-border-top-left-radius: 50% .3em;
-    -moz-border-radius-topleft: 50% .3em;
-    border-top-left-radius: 50% .3em;
+    -webkit-border-top-right-radius: 50% 0.3em;
+    -moz-border-radius-topright: 50% 0.3em;
+    border-top-right-radius: 50% 0.3em;
+    -webkit-border-top-left-radius: 50% 0.3em;
+    -moz-border-radius-topleft: 50% 0.3em;
+    border-top-left-radius: 50% 0.3em;
     margin-top: 1px;
     padding-top: 0.15em;
   }
 
   .mq-overarrow {
-    min-width: .5em;
+    min-width: 0.5em;
     border-top: 1px solid black;
     margin-top: 1px;
     padding-top: 0.2em;
@@ -461,7 +487,8 @@
       content: '';
       display: none;
     }
-    &.mq-arrow-left:before, &.mq-arrow-leftright:before {
+    &.mq-arrow-left:before,
+    &.mq-arrow-leftright:before {
       position: absolute;
       top: -0.48em;
       left: -0.1em;
@@ -472,7 +499,25 @@
       -webkit-transform: scaleX(-1);
       transform: scaleX(-1);
       filter: FlipH;
-      -ms-filter: "FlipH";
+      -ms-filter: 'FlipH';
     }
   }
+
+  .mq-limit {
+    padding: 0 0.2em;
+    text-align: center;
+    display: inline-block;
+  }
+
+  .mq-limit-label {
+    display: block;
+    width: 100%;
+  }
+
+  .mq-limit-sub {
+    float: right;
+    display: block;
+    width: 100%;
+    font-size: 80%;
+  }
 }
diff --git a/src/publicapi.ts b/src/publicapi.ts
index e982e0466..6e6e78555 100644
--- a/src/publicapi.ts
+++ b/src/publicapi.ts
@@ -102,6 +102,7 @@ class Options {
   typingAsteriskWritesTimesSymbol?: boolean;
   typingSlashWritesDivisionSymbol: boolean;
   typingPercentWritesPercentOf?: boolean;
+  customCharacters?: string | readonly string[];
   resetCursorOnBlur?: boolean | undefined;
   leftRightIntoCmdGoes?: 'up' | 'down';
   enableDigitGrouping?: boolean;
diff --git a/src/services/latex.ts b/src/services/latex.ts
index c19c0fb49..fe54ab105 100644
--- a/src/services/latex.ts
+++ b/src/services/latex.ts
@@ -67,7 +67,26 @@ var latexMathParser = (function () {
         return fail('unknown command: \\' + ctrlSeq);
       }
     });
-  var command = controlSequence.or(variable).or(number).or(symbol);
+  var loneAmpersand = regex(/^&/).then(() => {
+    // TODO - is Parser<MQNode> correct?
+    var cmdKlass = CharCmds['&'] || LatexCmds['&'];
+    if (cmdKlass) {
+      if (cmdKlass.constructor) {
+        var actualClass = cmdKlass as typeof TempSingleCharNode; // TODO - figure out how to know the difference
+        return new actualClass('&').parser();
+      } else {
+        var builder = cmdKlass as (c: string) => TempSingleCharNode; // TODO - figure out how to know the difference
+        return builder('&').parser();
+      }
+    } else {
+      return fail('unknown command: \\&');
+    }
+  });
+  var command = loneAmpersand
+    .or(controlSequence)
+    .or(variable)
+    .or(number)
+    .or(symbol);
   // Parsers yielding MathBlocks
   var mathGroup: Parser<MathBlock> = string('{')
     .then(function () {
diff --git a/test/unit/typing.test.js b/test/unit/typing.test.js
index 31942c44b..55be8667a 100644
--- a/test/unit/typing.test.js
+++ b/test/unit/typing.test.js
@@ -1387,7 +1387,7 @@ suite('typing with auto-replaces', function () {
 
     test('command is a built-in operator name', function () {
       var cmds = (
-        'Pr arg deg det dim exp gcd hom inf ker lg lim ln log max min sup' +
+        'Pr arg deg det dim exp gcd hom inf ker lg ln log max min sup' +
         ' limsup liminf injlim projlim Pr'
       ).split(' ');
       for (var i = 0; i < cmds.length; i += 1) {
@@ -1400,9 +1400,7 @@ suite('typing with auto-replaces', function () {
     test('built-in operator names even after auto-operator names overridden', function () {
       MQ.config({ autoOperatorNames: 'sin inf arcosh cosh cos cosec csc' });
       // ^ happen to be the ones required by autoOperatorNames.test.js
-      var cmds = 'Pr arg deg det exp gcd inf lg lim ln log max min sup'.split(
-        ' '
-      );
+      var cmds = 'Pr arg deg det exp gcd inf lg ln log max min sup'.split(' ');
       for (var i = 0; i < cmds.length; i += 1) {
         assert.throws(function () {
           MQ.config({ autoCommands: cmds[i] });