Lecture 1

• therefore

  
• sum

  
• in the set

  
• natural numbers

  
• implies

  
• for all values of

  
• there exists

  
• biconditional (if and only if)

  
• b is divisible by a

  
• end of proof

  
• inductive hypothesis

  
• a proposition is a predicate (true/false) that depends on the variable's value