# precondition: input x > 0 # postcondition (goal): y >= x x = readInt() #PREMISES FOR ATTACHED PROOF, IF ANY: # True #PREMISES FOR NEXT LINE: assert x > 0 #PREMISES FOR NEXT LINE: # (x > 0) """{ 1.OK x > 0 premise }""" #PREMISES FOR NEXT LINE: # (x > 0) y = 2 * x #PREMISES FOR ATTACHED PROOF, IF ANY: # (y == (2 * x)) # (x > 0) """{ 1.OK x > 0 premise 2.OK y == 2 * x premise 3.OK y > x algebra 1 2 }""" #PREMISES FOR NEXT LINE: # (y > x) x = x + 1 #PREMISES FOR ATTACHED PROOF, IF ANY: # (x == (x_old + 1)) # (y > x_old) """{ 1.OK y > x_old premise 2.OK x == x_old + 1 premise 3.OK x_old == x - 1 algebra 2 4.OK y > x - 1 subst 3 1 5.OK y >= x algebra 4 }""" #PREMISES FOR NEXT LINE: # (y >= x)