Let A = L(G1) where G1 is defined in Problem 2.25. Show that A is not a DCFL

(Hint: Assume that A is a DCFL and consider its DPDA P. Modify P so that its input alphabet is {a, b, c}. When it first enters an accept state, it pretends that c's are b's in the input from that point on. What langiage would the modified P accept?)

Problem 2.25 (Doesn't need to be solved, just for reference)

Let G1 be the following grammar. Use the DK-test to show that G1 is not a DCFG

R --> S | T

S --> aSb | ab

T --> aTbb | abb