In a cases* environment (from mathtools package), I try to enter math
mode in the "text column", but auctex doesn't let me enter a $.

So I have

\begin{equation}
  \label{eq:240}
  Tx=
  \begin{dcases*}
    1& if
  \end{dcases*}
\end{equation}

and after "if" a I try to enter a formula, but auctex says in the
minibuffer

"Math mode started with ‘equation’ cannot be closed with dollar"

I should be able to enter a $ in text mode.

Thanks.

Emacs  : GNU Emacs 28.1 (build 1, x86_64-redhat-linux-gnu, GTK+ Version
3.24.34, cairo version 1.17.6)
 of 2022-07-15
Package: 13.1.4

current state:
==============
(setq
 AUCTeX-date "2022-08-26"
 window-system 'x
 LaTeX-version "2e"
 TeX-style-path '("~/.emacs.d/auctex"
 "/home/apu/.emacs.d/elpa/auctex-13.1.4/style"
 "/home/apu/.emacs.d/auctex/auto"
 "/home/apu/.emacs.d/auctex/style" "auto" "style")
 TeX-auto-save t
 TeX-parse-self t
 TeX-master "main"
 TeX-command-list '(("TeX"
    "%(PDF)%(tex) %(file-line-error) %`%(extraopts) %S%(PDFout)%(mode)%'
%(output-dir) %t"
    TeX-run-TeX nil
    (plain-tex-mode ams-tex-mode texinfo-mode) :help
    "Run plain TeX")
   ("LaTeX" "%`%l%(mode)%' %T" TeX-run-TeX nil
    (latex-mode doctex-mode) :help "Run LaTeX")
   ("Makeinfo" "makeinfo %(extraopts) %(o-dir) %t"
    TeX-run-compile nil (texinfo-mode) :help
    "Run Makeinfo with Info output")
   ("Makeinfo HTML"
    "makeinfo %(extraopts) %(o-dir) --html %t"
    TeX-run-compile nil (texinfo-mode) :help
    "Run Makeinfo with HTML output")
   ("AmSTeX"
    "amstex %(PDFout) %`%(extraopts) %S%(mode)%' %(output-dir) %t"
    TeX-run-TeX nil (ams-tex-mode) :help "Run AMSTeX")
   ("ConTeXt"
    "%(cntxcom) --once --texutil %(extraopts) %(execopts)%t"
    TeX-run-TeX nil (context-mode) :help "Run ConTeXt once")
   ("ConTeXt Full" "%(cntxcom) %(extraopts) %(execopts)%t"
    TeX-run-TeX nil (context-mode) :help
    "Run ConTeXt until completion")
   ("BibTeX" "bibtex %(O?aux)" TeX-run-BibTeX nil
    (plain-tex-mode latex-mode doctex-mode ams-tex-mode
     texinfo-mode context-mode)
    :help "Run BibTeX")
   ("Biber" "biber %(output-dir) %s" TeX-run-Biber nil
    (plain-tex-mode latex-mode doctex-mode ams-tex-mode
     texinfo-mode)
    :help "Run Biber")
   ("Texindex" "texindex %s.??" TeX-run-command nil
    (texinfo-mode) :help "Run Texindex")
   ("Texi2dvi" "%(PDF)texi2dvi %t" TeX-run-command nil
    (texinfo-mode) :help "Run Texi2dvi or Texi2pdf")
   ("View" "%V" TeX-run-discard-or-function t t :help
    "Run Viewer")
   ("Print" "%p" TeX-run-command t t :help "Print the file")
   ("Queue" "%q" TeX-run-background nil t :help
    "View the printer queue" :visible TeX-queue-command)
   ("File" "%(o?)dvips %d -o %f " TeX-run-dvips t
    (plain-tex-mode latex-mode doctex-mode ams-tex-mode
     texinfo-mode)
    :help "Generate PostScript file")
   ("Dvips" "%(o?)dvips %d -o %f " TeX-run-dvips nil
    (plain-tex-mode latex-mode doctex-mode ams-tex-mode
     texinfo-mode)
    :help "Convert DVI file to PostScript")
   ("Dvipdfmx" "dvipdfmx -o %(O?pdf) %d" TeX-run-dvipdfmx nil
    (plain-tex-mode latex-mode doctex-mode ams-tex-mode
     texinfo-mode)
    :help "Convert DVI file to PDF with dvipdfmx")
   ("Ps2pdf" "ps2pdf %f %(O?pdf)" TeX-run-ps2pdf nil
    (plain-tex-mode latex-mode doctex-mode ams-tex-mode
     texinfo-mode)
    :help "Convert PostScript file to PDF")
   ("Glossaries" "makeglossaries %(d-dir) %s" TeX-run-command
    nil
    (plain-tex-mode latex-mode doctex-mode ams-tex-mode
     texinfo-mode)
    :help "Run makeglossaries to create glossary file")
   ("Index" "makeindex %(O?idx)" TeX-run-index nil
    (plain-tex-mode latex-mode doctex-mode ams-tex-mode
     texinfo-mode)
    :help "Run makeindex to create index file")
   ("upMendex" "upmendex %(O?idx)" TeX-run-index t
    (plain-tex-mode latex-mode doctex-mode ams-tex-mode
     texinfo-mode)
    :help "Run upmendex to create index file")
   ("Xindy" "texindy %s" TeX-run-command nil
    (plain-tex-mode latex-mode doctex-mode ams-tex-mode
     texinfo-mode)
    :help "Run xindy to create index file")
   ("Check" "lacheck %s" TeX-run-compile nil (latex-mode)
    :help "Check LaTeX file for correctness")
   ("ChkTeX" "chktex -v6 %s" TeX-run-compile nil (latex-mode)
    :help "Check LaTeX file for common mistakes")
   ("Spell" "(TeX-ispell-document \"\")" TeX-run-function nil
    t :help "Spell-check the document")
   ("Clean" "TeX-clean" TeX-run-function nil t :help
    "Delete generated intermediate files")
   ("Clean All" "(TeX-clean t)" TeX-run-function nil t :help
    "Delete generated intermediate and output files")
   ("Other" "" TeX-run-command t t :help
    "Run an arbitrary command")
   )
 )