\newtheorem* defines an unnumbered theorem instead of leaking

[tannevaled]

amsthm's starred form was unhandled. The star stopped readBraceName dead: no name
was read, the environment stayed undefined, and the star and the heading were
left in the input to be typeset. One paper opened on a spurious page of its own
carrying

*theoremTheorem *namedconjectureConjecture

and then set the three bodies of its theorem environment as plain paragraphs.

The fix

The star is read, and a starred \newtheorem defines the same environment with no
counter, no \the<env>, and a heading with no number — \@beginthmnonum, a sibling
of \@begintheorem without its \ #2, so the head reads Theorem. rather than
Theorem .. The optional note (Theorem (Smith).) goes through the same
continuation as a numbered theorem.

Measured

39 uses across 17 of the 200 arXiv papers. Over the 157 with a tectonic
reference:

	before	after
page error	574	535
exact	23	24
within 1 page	61	66
within 2 pages	96	103
signed bias	+36	−19

The largest single move of the current campaign, and it comes from three lines of
argument parsing: the papers were not merely mis-set, they were carrying macro
arguments as body text and losing every theorem statement's structure.

Two tests, both failing on main: the star must not be typeset, the starred
environment must carry no number while its numbered sibling still counts, and the
optional note must survive.

🤖 Generated with Claude Code