[MASSMAIL] Clarification on View Privileges and Operator Execution in PostgreSQL

I am recently studying about operators and views and I had doubts in two small things

1. I know if a view (security definer) is accessing a table then it is getting accessed by view owners privileges 

but what about the view which contains inbuilt operators or inbuilt functions with whose privileges those will be executed. Eg.

SET ROLE postgres;

CREATE TABLE x(id INT);

CREATE VIEW v AS SELECT * FROM x WHERE id > 100;

CREATE ROLE alex;

GRANT SELECT ON v TO alex;

SET ROLE alex;

SELECT * FROM v;

Now table x will be accessed (SELECT * FROM x) with "postgres" privileges but who will execute the 

underlying function inside the ( > ) operator ? Is it postgres or alex?

2. What if I used a user defined operator in the above example, then with whose privileges that operator will be executed?

Thanks

Ayush Vatsa

SDE AWS