fix: pick up math-expressions fix for lost matrix entries of -1

[dqnykamp]

Bumps math-expressions from 2.0.0-alpha95 to 2.0.0-alpha96, which fixes wrong answers and a hard failure in matrix, vector, and tuple arithmetic.

The bug

<matrix name="A"><row>-1 5</row><row>-1 -3</row></matrix>
<matrix name="B"><row>-2 -1</row><row>-3 -5</row></matrix>
<matrix name="C"><row>-2 -4</row><row>1 -1</row></matrix>

<math name="ans" simplify>$A + $B - $C</math>
$ans.matrix[2][2]

The (2,2) entry came out as -8 instead of -7. With different numbers — an <answer> checking a student's matrix, say — the same document instead failed with TypeError: Cannot read properties of undefined (reading '0') and rendered nothing.

Both come from one defect in the simplifier. Distributing the minus sign over C's entries turns the -1 entry into the product (-1)(-1); the pass that merges numeric factors omitted a coefficient of 1 from its result, which for a product of nothing but numbers left an empty multiplication that later evaluated to undefined. The entry then vanished from its sum. Which symptom the reader saw depended on how the remaining addends sorted around the missing one: a negative partial sum silently dropped it, a positive one dereferenced it and threw.

Ordinary scalar arithmetic never hit this, since numbers are evaluated before the pass runs. Only products built afterwards — those from distributing a scalar over a matrix, vector, or tuple — could reach it, so entries of -1 in a subtracted matrix were the common trigger.

Fixed upstream in Doenet/math-expressions#89, released as 2.0.0-alpha96.

Verification

Both documents now give [[-1, 8], [-5, -7]] and [[9, 2], [-7, -4]], with $ans.matrix[2][2] reading -7.

matrix, matrixinput, math, and the linearAlgebra suites pass against the new version.

🤖 Generated with Claude Code