Fundamentals of mathematics, algebra and geometry. Official website of Yanshan University shows that the postgraduate re-examination subjects are:

1. Mathematical basis: including advanced mathematics, linear algebra, probability theory and mathematical statistics.

2. Mathematical analysis: including real analysis, complex analysis and functional analysis.

3. Algebra and geometry: including abstract algebra, group theory, ring theory, domain theory, topology, etc.

4. Applied mathematics: including partial differential equations, numerical analysis, cybernetics, optimization theory, etc.