I have a question that says:
Construct a PDA that accepts the language {a^i b^j | 0 <= i <= j}
and this is the given solution:
δ ( q0, a, z ) = ( q0, az ) read a, push a
δ ( q0, a, a ) = ( q0, aa )
δ ( q0, b, a ) = ( q1, λ ) read b, pop a
δ ( q1, b, a ) = ( q1, λ )
δ ( q1, λ, z ) = ( qf, z ) end of string, stack empty
δ ( q1, b, z ) = ( q1, z ) check the additional b’s
but to my understanding a possible input string would start with b, since i could be 0 and a^i could be 1, while j could be 1 and b^j could be b, wouldn't this mean that there should be a line that says:
δ ( q0, b, z ) = ( q1, z ) ?
or am I misunderstanding something?