This is pdfTeX, Version 3.141592653-2.6-1.40.22 (TeX Live 2021) (preloaded format=pdflatex 2021.10.22)  19 JUN 2022 08:33
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**introduction.tex
(./introduction.tex
LaTeX2e <2020-10-01> patch level 4
L3 programming layer <2021-02-18>
./introduction.tex:1: Undefined control sequence.
l.1 \section
            {Introduction}
? 
./introduction.tex:1: Emergency stop.
l.1 \section
            {Introduction}
End of file on the terminal!

 
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./introduction.tex:1:  ==> Fatal error occurred, no output PDF file produced!
