Engineering
Engineering, 18.10.2019 17:10, gevaughn600

In this problem, we’ll use the following definitions of operations on languages (sets of strings) a, b:

union a ∪ b = {x | x ∈ a or x ∈ b}
concatenation a ◦ b = {xy | x ∈ a and y ∈ b}
star a* = {x1x2 . . xk | k ∈ z and k ≥ 0 and each xi ∈ a}
for each of the following sets of strings over the alphabet {a, b}, answer the following questions:
(1) is ε (the empty string) in the set?
(2) what is an example of a string over {a, b} of length at least 2 that is in the set (or why isn’t there such an example)?
(3) what is an example of a string over this alphabet of length at least 2 that is not in the set (or why isn’t there such an example)?
(a) { w | w ∈ {a, b}*}
(b) { w | w ∈ {ab}*}
(c) { a, aa } ◦ { b, bb }
(d) { a } ∪ { aa } ∪ { ab } ∪ { ba }

answer
Answers: 3

Other questions on the subject: Engineering

image
Engineering, 04.07.2019 18:10, abdirahmansoloman
Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?
Answers: 1
image
Engineering, 04.07.2019 18:10, 19deleonl
Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.
Answers: 2
image
Engineering, 04.07.2019 18:10, siri5645
At 12 noon, the count in a bacteria culture was 400; at 4: 00 pm the count was 1200 let p(t) denote the bacteria cou population growth law. find: (a) an expression for the bacteria count at any time t (b) the bacteria count at 10 am. (c) the time required for the bacteria count to reach 1800.
Answers: 1
image
Engineering, 04.07.2019 18:10, nandalabella06
True or false (explain) (110)[111] is a slip system in bcc metals . the {111} family in fcc contains 8 planes. resolved shear stress (rss) in single crystals is just related to the applied stress. critical resolved shear stress (crss) in single crystal metals is direct proportional to the number of defects in the structure
Answers: 2
Do you know the correct answer?
In this problem, we’ll use the following definitions of operations on languages (sets of strings) a,...

Questions in other subjects:

Konu
Mathematics, 25.10.2020 01:00
Konu
SAT, 25.10.2020 01:00
Konu
Mathematics, 25.10.2020 01:00
Konu
Mathematics, 25.10.2020 01:00
Konu
History, 25.10.2020 01:00