C++ set容器问题

Question

一个Person类 没有重载 == 只写了 < 的仿函数 ，然后 用set 存 Person对象
我没重写== ， set 的find 是怎么判断 两个Person相等的？而且不报错

class Person{
public:
    int age;
    string name;
    Person(){}
    Person(int a,string s):age(a),name(s){
    }
    ~Person(){
    }
    /*const bool operator==(const Person& p) const{
        return (this->age == p.age);
    }*/
};

class mycomp{
public:
    bool operator()(const Person& a,const Person& b){
        return a.age < b.age;
    }
};

Answer 1

a == b可以等价于!(a < b) && !(b < a)

https://en.cppreference.com/w/cpp/container/set

Everywhere the standard library uses the Compare requirements, uniqueness is determined by using the equivalence relation. In imprecise terms, two objects a and b are considered equivalent if neither compares less than the other: !comp(a, b) && !comp(b, a).