graph TD
    DefFact("DefFact Factorial")
    DefSum("DefSum Sum principle")
    DefProd("DefProd Product principle")
    PermNoRep("PermNoRep Permutations no rep")
    Pigeonhole("Pigeonhole Pigeonhole principle")
    InclExcl("InclExcl Inclusion-exclusion")
    InclExcl3("InclExcl3 Incl-excl 3 sets")
    Derange("Derange Derangements")
    Stirling2("Stirling2 Stirling numbers")
    DefFact --> PermNoRep
    DefProd --> PermNoRep
    DefSum --> Pigeonhole
    DefSum --> InclExcl
    InclExcl --> InclExcl3
    InclExcl --> Derange
    PermNoRep --> Derange
    DefSum --> Stirling2
    DefProd --> Stirling2
    classDef axiom fill:#e74c3c,color:#fff,stroke:#c0392b
    classDef definition fill:#3498db,color:#fff,stroke:#2980b9
    classDef theorem fill:#1abc9c,color:#fff,stroke:#16a085
    class DefFact,DefSum,DefProd definition
    class PermNoRep,Pigeonhole,InclExcl,InclExcl3,Derange,Stirling2 theorem