\documentclass{article}
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\usetikzlibrary{svg.path}
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\begin{document}
A\sagelogo B
\large
A\sagelogo B
\Large
A\sagelogo B
\LARGE
A\sagelogo B
\end{document}
AFAIK gibt es das nicht als Font und nicht einmal als Vektorgrafik. In der (PDF-)Anleitung verwenden sie selbst
Sage
bzw.Sage\TeX
. Ansonsten findet man vom Logo wohl nur JPEGs und PNGs. Man könnte aus einem der SVG-Werbebanner den relevanten Teil ausschneiden. Prinzipiell sollte es aber auch einfach möglich sein, das mittikz
nachzubauen. Dann hätte man es wenigstens frei skalierbar und könnte sogar die Liniendicke leicht an die verwendete Schrift anpassen.