<article class="ltx_document">
<div id="p1" class="ltx_para">
<p class="ltx_p">For vector-valued variables, we would write the random variable as <math id="p1.m1" class="ltx_Math" alttext="\bm{\mathrm{x}}" display="inline"><semantics><mi>𝐱</mi><annotation encoding="application/x-llamapun">bold_x</annotation></semantics></math> and one of its values as <math id="p1.m2" class="ltx_Math" alttext="\bm{x}" display="inline"><semantics><mi>𝒙</mi><annotation encoding="application/x-llamapun">bold_italic_x</annotation></semantics></math>.</p>
</div>
<div id="p2" class="ltx_para">
<p class="ltx_p">We want array lexemes to be compositionally exposing their contents:</p>
<table id="S0.Ex1" class="ltx_equation ltx_eqn_table">

<tbody><tr class="ltx_equation ltx_eqn_row ltx_align_baseline">
<td class="ltx_eqn_cell ltx_eqn_center_padleft"></td>
<td class="ltx_eqn_cell ltx_align_center"><math id="S0.Ex1.m1" class="ltx_Math" alttext="\begin{array}[]{cc}a+1&amp;b-2\\&#10;c+3&amp;d-4\end{array}" display="block"><semantics><mtable columnspacing="5pt" displaystyle="true" rowspacing="0pt"><mtr><mtd><mrow><mi>a</mi><mo>+</mo><mn>1</mn></mrow></mtd><mtd><mrow><mi>b</mi><mo>−</mo><mn>2</mn></mrow></mtd></mtr><mtr><mtd><mrow><mi>c</mi><mo>+</mo><mn>3</mn></mrow></mtd><mtd><mrow><mi>d</mi><mo>−</mo><mn>4</mn></mrow></mtd></mtr></mtable><annotation encoding="application/x-llamapun">start_ARRAY start_ROW start_CELL italic_a + 1 end_CELL start_CELL italic_b - 2 end_CELL end_ROW start_ROW start_CELL italic_c + 3 end_CELL start_CELL italic_d - 4 end_CELL end_ROW end_ARRAY</annotation></semantics></math></td>
<td class="ltx_eqn_cell ltx_eqn_center_padright"></td></tr></tbody>
</table>
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<div id="p3" class="ltx_para">
<p class="ltx_p">We also want atoms to be compositionally exposing their contents:</p>
<table id="S0.Ex2" class="ltx_equation ltx_eqn_table">

<tbody><tr class="ltx_equation ltx_eqn_row ltx_align_baseline">
<td class="ltx_eqn_cell ltx_eqn_center_padleft"></td>
<td class="ltx_eqn_cell ltx_align_center"><math id="S0.Ex2.m1" class="ltx_Math" alttext="1+\left(\text{$x$ if $x&lt;0$ else $y$}\right)" display="block"><semantics><mrow><mn>1</mn><mo>+</mo><mrow><mo>(</mo><mrow><mi>x</mi><mtext> if </mtext><mrow><mi>x</mi><mo>&lt;</mo><mn>0</mn></mrow><mtext> else </mtext><mi>y</mi></mrow><mo>)</mo></mrow></mrow><annotation encoding="application/x-llamapun">1 + ( italic_x if italic_x &lt; 0 else italic_y )</annotation></semantics></math></td>
<td class="ltx_eqn_cell ltx_eqn_center_padright"></td></tr></tbody>
</table>
</div>
<div id="p4" class="ltx_para">
<p class="ltx_p">We have explicit font shape/weight for alphabetic tokens when they look like text, compare <math id="p4.m1" class="ltx_Math" alttext="a" display="inline"><semantics><mi>a</mi><annotation encoding="application/x-llamapun">italic_a</annotation></semantics></math> to <math id="p4.m2" class="ltx_Math" alttext="\mathrm{a}" display="inline"><semantics><mi mathvariant="normal">a</mi><annotation encoding="application/x-llamapun">roman_a</annotation></semantics></math>.
Also <math id="p4.m3" class="ltx_Math" alttext="\mathit{func}" display="inline"><semantics><mi>𝑓𝑢𝑛𝑐</mi><annotation encoding="application/x-llamapun">italic_func</annotation></semantics></math> to <math id="p4.m4" class="ltx_Math" alttext="\operatorname{func}" display="inline"><semantics><mi>func</mi><annotation encoding="application/x-llamapun">roman_func</annotation></semantics></math> and <math id="p4.m5" class="ltx_Math" alttext="\mathrm{func}" display="inline"><semantics><mi>func</mi><annotation encoding="application/x-llamapun">roman_func</annotation></semantics></math>.</p>
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<div id="p5" class="ltx_para">
<p class="ltx_p">Also, be aware of natural uses of the text macro:</p>
<table id="S0.Ex3" class="ltx_equation ltx_eqn_table">

<tbody><tr class="ltx_equation ltx_eqn_row ltx_align_baseline">
<td class="ltx_eqn_cell ltx_eqn_center_padleft"></td>
<td class="ltx_eqn_cell ltx_align_center"><math id="S0.Ex3.m1" class="ltx_Math" alttext="\int_{0}^{\infty}x\,dx=\text{zero, \it yes 0}" display="block"><semantics><mrow><mrow><msubsup><mo>∫</mo><mn>0</mn><mi mathvariant="normal">∞</mi></msubsup><mrow><mi>x</mi><mo lspace="0.170em">⁢</mo><mrow><mo rspace="0em">𝑑</mo><mi>x</mi></mrow></mrow></mrow><mo>=</mo><mrow><mtext>zero, </mtext><mtext class="ltx_mathvariant_italic">yes 0</mtext></mrow></mrow><annotation encoding="application/x-llamapun">∫ start_POSTSUBSCRIPT 0 end_POSTSUBSCRIPT start_POSTSUPERSCRIPT ∞ end_POSTSUPERSCRIPT italic_x italic_d italic_x = zero, italic_yes italic_0</annotation></semantics></math></td>
<td class="ltx_eqn_cell ltx_eqn_center_padright"></td></tr></tbody>
</table>
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