da5002_2026T1_Q1_NA.pdf
Mathematical Foundations of Generative AI · Quiz 1 · Jan 2026
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Question 2 MCQ · 3.0 marks
The [[IMAGE:c3240b78982312ff_3_2]] -divergence is written as
[[IMAGE:c3240b78982312ff_3_3]]
with [[IMAGE:c3240b78982312ff_3_4]] convex and [[IMAGE:c3240b78982312ff_3_5]] . Which choice of [[IMAGE:c3240b78982312ff_3_6]] gives the reverse KL divergence [[IMAGE:c3240b78982312ff_3_7]] ?






[[IMAGE:c3240b78982312ff_3_8]]

[[IMAGE:c3240b78982312ff_3_9]]

[[IMAGE:c3240b78982312ff_3_10]]

[[IMAGE:c3240b78982312ff_3_11]]

A published solution is not available for this question yet.
Question 3 MCQ · 3.0 marks
Total variation distance [[IMAGE:c3240b78982312ff_4_12]] corresponds to which [[IMAGE:c3240b78982312ff_4_13]] in the
same [[IMAGE:c3240b78982312ff_4_14]] -divergence form?



[[IMAGE:c3240b78982312ff_4_15]]

[[IMAGE:c3240b78982312ff_4_16]]

[[IMAGE:c3240b78982312ff_4_17]]

[[IMAGE:c3240b78982312ff_4_18]]

A published solution is not available for this question yet.
Question 4 MCQ · 3.0 marks
Consider [[IMAGE:c3240b78982312ff_4_19]] (forward KL). Its convex conjugate is
[[IMAGE:c3240b78982312ff_4_20]]
Which is the correct closed form for [[IMAGE:c3240b78982312ff_4_21]] ?



[[IMAGE:c3240b78982312ff_4_22]]

[[IMAGE:c3240b78982312ff_4_23]]

[[IMAGE:c3240b78982312ff_4_24]]

[[IMAGE:c3240b78982312ff_4_25]]

A published solution is not available for this question yet.
Question 5 MCQ · 3.0 marks
Let the discriminator be parameterized via a logit [[IMAGE:c3240b78982312ff_4_26]] : [[IMAGE:c3240b78982312ff_4_27]] , [[IMAGE:c3240b78982312ff_4_28]] . If
[[IMAGE:c3240b78982312ff_5_29]] , then the optimal logit satisfies:




[[IMAGE:c3240b78982312ff_5_30]]

[[IMAGE:c3240b78982312ff_5_31]]

[[IMAGE:c3240b78982312ff_5_32]]

[[IMAGE:c3240b78982312ff_5_33]]

A published solution is not available for this question yet.
Question 6 MCQ · 3.0 marks
[[IMAGE:c3240b78982312ff_5_34]]

[[IMAGE:c3240b78982312ff_5_35]]

[[IMAGE:c3240b78982312ff_5_36]]

[[IMAGE:c3240b78982312ff_5_37]]

[[IMAGE:c3240b78982312ff_5_38]]

A published solution is not available for this question yet.
Question 7 MCQ · 3.0 marks
Let [[IMAGE:c3240b78982312ff_6_39]] . Compare generator gradients w.r.t. the discriminator logit [[IMAGE:c3240b78982312ff_6_40]] for:
[[IMAGE:c3240b78982312ff_6_41]]
If [[IMAGE:c3240b78982312ff_6_42]] , which magnitude is correct?




[[IMAGE:c3240b78982312ff_6_43]] , [[IMAGE:c3240b78982312ff_6_44]]


[[IMAGE:c3240b78982312ff_6_45]] , [[IMAGE:c3240b78982312ff_6_46]]


Both are approximately [[IMAGE:c3240b78982312ff_6_47]]

Both are approximately [[IMAGE:c3240b78982312ff_6_48]]

A published solution is not available for this question yet.
Question 8 MCQ · 3.0 marks
WGAN-GP adds the penalty
[[IMAGE:c3240b78982312ff_6_49]]
If for a sampled [[IMAGE:c3240b78982312ff_6_50]] you measure [[IMAGE:c3240b78982312ff_6_51]] and [[IMAGE:c3240b78982312ff_6_52]] , what is the penalty contribution
for that sample?




0.3
9.0
3.0
0.9
A published solution is not available for this question yet.
Question 9 MCQ · 3.0 marks
If the true data is conditional [[IMAGE:c3240b78982312ff_6_53]] and the generator matches it perfectly, then the marginal of
generated samples satisfies:

[[IMAGE:c3240b78982312ff_7_54]]

[[IMAGE:c3240b78982312ff_7_55]] for a fixed [[IMAGE:c3240b78982312ff_7_56]]


[[IMAGE:c3240b78982312ff_7_57]]

[[IMAGE:c3240b78982312ff_7_58]]

A published solution is not available for this question yet.
Question 10 MCQ · 2.0 marks
In PyTorch, you run:
[[IMAGE:c3240b78982312ff_7_59]]
without calling **zero_grad()**. What happens to [[IMAGE:c3240b78982312ff_7_60]] ?


It is overwritten by the second backward pass.
It becomes zero due to autograd safety.
It accumulates (adds) gradients from both backward passes.
It becomes NaN deterministically.
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Question 11 MCQ · 2.0 marks
For fixed [[IMAGE:c3240b78982312ff_7_61]] , the pointwise optimal discriminator [[IMAGE:c3240b78982312ff_7_62]] for the minimax GAN is:


[[IMAGE:c3240b78982312ff_7_63]]

[[IMAGE:c3240b78982312ff_7_64]]

[[IMAGE:c3240b78982312ff_7_65]]

[[IMAGE:c3240b78982312ff_8_66]]

A published solution is not available for this question yet.
Question 12 MCQ · 2.0 marks
Assume [[IMAGE:c3240b78982312ff_8_67]] and [[IMAGE:c3240b78982312ff_8_68]] are disjoint and the discriminator reaches [[IMAGE:c3240b78982312ff_8_69]] . Consider the
minimax generator loss
[[IMAGE:c3240b78982312ff_8_70]]
Which statement about [[IMAGE:c3240b78982312ff_8_71]] is correct?





It is nonzero and large because [[IMAGE:c3240b78982312ff_8_72]] has high curvature.

It is exactly zero (vanishing gradient) because [[IMAGE:c3240b78982312ff_8_73]] and [[IMAGE:c3240b78982312ff_8_74]] is locally
constant on generated samples.


It equals [[IMAGE:c3240b78982312ff_8_75]] .

It diverges to infinity.
A published solution is not available for this question yet.
Question 13 MCQ · 2.0 marks
(Classifier-guided sampler) Suppose you want an acceptance probability of the form
[[IMAGE:c3240b78982312ff_8_76]]
and you approximate [[IMAGE:c3240b78982312ff_8_77]] If [[IMAGE:c3240b78982312ff_8_78]] and [[IMAGE:c3240b78982312ff_8_79]] , what is [[IMAGE:c3240b78982312ff_8_80]] ?





0.30
0.60
0.75
1.00
A published solution is not available for this question yet.
Question 14 MCQ · 2.0 marks
Which objective correctly represents a conditional GAN with condition [[IMAGE:c3240b78982312ff_9_81]] ?

[[IMAGE:c3240b78982312ff_9_82]]

[[IMAGE:c3240b78982312ff_9_83]]

[[IMAGE:c3240b78982312ff_9_84]]

[[IMAGE:c3240b78982312ff_9_85]]

A published solution is not available for this question yet.
Question 15 MCQ · 2.0 marks
In Wasserstein GAN, the discriminator is replaced by a critic [[IMAGE:c3240b78982312ff_9_86]] . Which statement is correct?

[[IMAGE:c3240b78982312ff_9_87]] due to sigmoid, and must be calibrated probabilities.

[[IMAGE:c3240b78982312ff_9_88]] must output the exact density [[IMAGE:c3240b78982312ff_9_89]] .


[[IMAGE:c3240b78982312ff_9_90]] (no sigmoid) and is constrained to be 1-Lipschitz.

[[IMAGE:c3240b78982312ff_9_91]] must be a classifier with softmax outputs.

A published solution is not available for this question yet.
Question 16 MCQ · 2.0 marks
(Kantorovich–Rubinstein dual) The Wasserstein-1 distance can be written as:
[[IMAGE:c3240b78982312ff_10_92]]

[[IMAGE:c3240b78982312ff_10_93]]

[[IMAGE:c3240b78982312ff_10_94]]

[[IMAGE:c3240b78982312ff_10_95]]

A published solution is not available for this question yet.
Question 17 MCQ · 2.0 marks
“Latent regression” inversion trains an encoder / regressor [[IMAGE:c3240b78982312ff_10_96]] so that:

[[IMAGE:c3240b78982312ff_10_97]] and [[IMAGE:c3240b78982312ff_10_98]]


[[IMAGE:c3240b78982312ff_10_99]] and [[IMAGE:c3240b78982312ff_10_100]]


[[IMAGE:c3240b78982312ff_10_101]]

[[IMAGE:c3240b78982312ff_10_102]] directly estimates [[IMAGE:c3240b78982312ff_10_103]]


A published solution is not available for this question yet.
Question 18 MCQ · 2.0 marks
In BiGAN, what does the discriminator receive as “real” vs “fake” inputs?
Real: [[IMAGE:c3240b78982312ff_10_104]] ; Fake: [[IMAGE:c3240b78982312ff_10_105]] only


Real: [[IMAGE:c3240b78982312ff_10_106]] ; Fake: [[IMAGE:c3240b78982312ff_10_107]] only


Real: pairs [[IMAGE:c3240b78982312ff_10_108]] with [[IMAGE:c3240b78982312ff_10_109]] ; Fake: pairs [[IMAGE:c3240b78982312ff_10_110]] with [[IMAGE:c3240b78982312ff_10_111]]




Real: pairs [[IMAGE:c3240b78982312ff_11_112]] sampled jointly from [[IMAGE:c3240b78982312ff_11_113]] ; Fake: none


A published solution is not available for this question yet.
Question 19 MCQ · 2.0 marks
In WGAN, why are multiple critic updates typically performed per generator update? The most
accurate reason is:
The generator has no gradients unless the critic is exactly optimal, so you
must fully converge the critic each time.
The critic should be kept closer to its optimum so its gradients provide a
meaningful approximation to the Wasserstein distance and yield informative directions for
updating θ.
Multiple critic steps ensure the critic output becomes a probability.
It is required only when using sigmoid outputs.
A published solution is not available for this question yet.
Question 20 MCQ · 2.0 marks
For 1D Gaussian features, let real features be [[IMAGE:c3240b78982312ff_11_114]] and generated features be [[IMAGE:c3240b78982312ff_11_115]] .
The FID simplifies to
[[IMAGE:c3240b78982312ff_11_116]]
If [[IMAGE:c3240b78982312ff_11_117]] , [[IMAGE:c3240b78982312ff_11_118]] , [[IMAGE:c3240b78982312ff_11_119]] , [[IMAGE:c3240b78982312ff_11_120]] , what is the FID?







1
2
3
5
A published solution is not available for this question yet.
Question 21 MCQ · 2.0 marks
At an ideal BiGAN equilibrium (infinite capacity, optimal discriminator), the matched joint
distributions imply most directly that:
[[IMAGE:c3240b78982312ff_12_121]] is independent of [[IMAGE:c3240b78982312ff_12_122]] .


The joint distributions of [[IMAGE:c3240b78982312ff_12_123]] and [[IMAGE:c3240b78982312ff_12_124]] match.


Only marginals match: [[IMAGE:c3240b78982312ff_12_125]] , but nothing about [[IMAGE:c3240b78982312ff_12_126]] .


[[IMAGE:c3240b78982312ff_12_127]] must be linear.

A published solution is not available for this question yet.
Question 22 MCQ · 1.0 marks
The original minimax GAN objective is:
[[IMAGE:c3240b78982312ff_12_128]]

[[IMAGE:c3240b78982312ff_12_129]]

[[IMAGE:c3240b78982312ff_12_130]]

[[IMAGE:c3240b78982312ff_12_131]]

A published solution is not available for this question yet.
Question 23 MCQ · 1.0 marks
Given a trained generator [[IMAGE:c3240b78982312ff_12_132]] and a target image [[IMAGE:c3240b78982312ff_12_133]] , “GAN inversion via optimization” computes:


[[IMAGE:c3240b78982312ff_12_134]]

[[IMAGE:c3240b78982312ff_12_135]]

[[IMAGE:c3240b78982312ff_13_136]] for random [[IMAGE:c3240b78982312ff_13_137]]


[[IMAGE:c3240b78982312ff_13_138]]

A published solution is not available for this question yet.