BigOrdinals.dfy(18,11): Error: a negative integer cannot be converted to an ORDINAL
BigOrdinals.dfy(20,11): Error: value to be converted might be bigger than every natural number
BigOrdinals.dfy(35,13): Error: assertion might not hold
BigOrdinals.dfy(53,13): Error: assertion might not hold
BigOrdinals.dfy(64,15): Error: ORDINAL subtraction might underflow a limit ordinal (that is, RHS might be too large)
BigOrdinals.dfy(66,15): Error: ORDINAL subtraction might underflow a limit ordinal (that is, RHS might be too large)
BigOrdinals.dfy(68,15): Error: ORDINAL subtraction might underflow a limit ordinal (that is, RHS might be too large)
BigOrdinals.dfy(73,15): Error: ORDINAL subtraction might underflow a limit ordinal (that is, RHS might be too large)
BigOrdinals.dfy(88,13): Error: assertion might not hold
BigOrdinals.dfy(113,9): Error: value does not satisfy the subset constraints of 'ConstrainedOrdinal'
BigOrdinals.dfy(120,9): Error: value does not satisfy the subset constraints of 'ConstrainedOrdinal'

Dafny program verifier finished with 3 verified, 11 errors
