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2 changes: 1 addition & 1 deletion src/paper/references.bib
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Expand Up @@ -884,7 +884,7 @@ @article{NavarroVeszteg2020
@article{NydeggerOwen1974,
title = {Two-person bargaining: An experimental test of the Nash axioms},
author = {Nydegger, R.V. and Owen, G.},
year = {1874},
year = {1974},
pages = {239--249},
volume = {3},
journal = {International Journal of Game Theory},
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92 changes: 56 additions & 36 deletions src/presentation/defense.qmd
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Expand Up @@ -37,7 +37,7 @@ format:
:::

::: {.fragment}
- Many of such situations are characterized by an **imbalance of power**
- Many such situations are characterized by **power imbalance**
- Employer vs. employees
- Driver vs. passengers
:::
Expand Down Expand Up @@ -70,7 +70,7 @@ format:
## This thesis

::: {.fragment}
- Focus on the case of
- Focus on
- Predictions from **cooperative game theory**
- **One** (few) **central player**(s) and many smaller ones
:::
Expand Down Expand Up @@ -201,7 +201,7 @@ Same idea as with the Nash bargaining solution
- Axiomatic reasoning
- The Shapley-value is the only sharing rule that satisfies a **nice set of axioms**: efficiency, symmetry, linearity, dummy player axiom [@shapley1953additive]
- **Bargaining foundations**
- The value arises as the subgame-perfect equilibrium of various alternating-offer bargaining games [e.g., @gul1989bargaining; @winter1994demand; @hart1996bargaining; @stole1996intra; @inderst2003bargaining]
- Subgame-perfect equilibrium of various alternating-offer bargaining games [e.g., @gul1989bargaining; @winter1994demand; @hart1996bargaining; @stole1996intra; @inderst2003bargaining]
- A **tractable and sensible-looking** gain-sharing rule
- Comparative statics show that it behaves as one would expect

Expand Down Expand Up @@ -273,7 +273,7 @@ Set of all players: $N = \{P, A_1, \dots, A_n\}$
$$
v(S) = \begin{cases}
0 & \text{if } P \notin S \\
f\left(\frac{\#_A (S)}{n}\right) & \text{otherwise}.
f\left(\frac{\#_A (S)}{n}\right) & \text{otherwise}
\end{cases}
$$
:::
Expand All @@ -290,22 +290,22 @@ $$

:::: {.columns}

::: {.column width="37%"}
::: {.column width="42%"}

Characteristic fct.:
$$
\scriptsize
v(S) = \begin{cases}
0 & \text{if } P \notin S \\
f\left(\frac{\#_A (S)}{n}\right) & \text{o/w}.
f\left(\frac{\#_A (S)}{n}\right) & \text{o/w}
\end{cases}
$$

::: {.fragment .fade-in fragment-index=2}
Shapley value:
$$
\scriptsize
\varphi_P^n(f) = \frac{1}{n+1} \sum_{k=0}^{n} f(k)
\varphi_P^n(f) = \frac{1}{n+1} \sum_{k=0}^{n} f(k/n)
$$
:::
::: {.fragment .fade-in fragment-index=5}
Expand All @@ -317,9 +317,6 @@ $$

:::

::: {.column width=5%}
:::

::: {.column width="58%"}

::: {.r-stack}
Expand Down Expand Up @@ -356,22 +353,22 @@ $$

:::: {.columns}

::: {.column width="37%"}
::: {.column width="42%"}

Characteristic fct.:
$$
\scriptsize
v(S) = \begin{cases}
0 & \text{if } P \notin S \\
f\left(\frac{\#_A (S)}{n}\right) & \text{o/w}.
f\left(\frac{\#_A (S)}{n}\right) & \text{o/w}
\end{cases}
$$

::: {.fragment fragment-index=1}
Random order value:
$$
\scriptsize
\varphi_P^n(f) = \sum_{k=0}^{n} {\color{RoyalBlue}\Pr(|\mathrm{prec}P| = k)} f(k)
\varphi_P^n(f) = \sum_{k=0}^{n} {\color{RoyalBlue}\Pr(|\mathrm{prec}P| = k)} f(k/n)
$$
:::
::: {.fragment fragment-index=2}
Expand All @@ -383,10 +380,10 @@ $$

:::

::: {.column width=5%}
::: {.column width=4%}
:::

::: {.column width="58%"}
::: {.column width="52%"}

::: {.highlight-block .fragment fragment-index=2 .smaller}
**Theorem 1.1.**
Expand Down Expand Up @@ -765,9 +762,9 @@ Weighted value with **$\lambda_1 < \lambda_2$**
:::

::: {.fragment}
- Random order values are a **convenient tool** for modeling bargaining
- Random order values are a **convenient tool** for modeling bargaining in this setting
- **Analytically tractable**
- More **flexible** than the Shapley value or the we
- More **flexible** than the Shapley value or the weighed value
- **Sensible** in terms of comparative statics
:::

Expand All @@ -782,7 +779,7 @@ Hybrid platforms and bargaining power
::: {.fragment}
- Hybrid platforms are
- Getting more and more common
- Seemingly obvious concerns and high-profile competition policy cases
- Apparent concerns and high-profile competition policy cases
- Despite this, relatively little research
:::
::: {.fragment}
Expand All @@ -799,7 +796,7 @@ Examine the bargaining power implications of hybrid platforms and their welfare

::: {.fragment}
- **Shapley-value** based bargaining rule
- Analytically more **tractable**
- Analytically **tractable**
- Has **bargaining microfoundations** [e.g., @hart1996bargaining; @stole1996intra]
- Has precedents in the IO literature [e.g., @hart1990property; @montez2007downstream]
:::
Expand Down Expand Up @@ -926,7 +923,7 @@ Utility function: @sec-utility-function
::: {.fragment}
- Assume that the platform prices its products as if they were made by separate, competitive sellers
- Possible interpretation: profit-maximizing subsidiaries
- More importantly: "best case scenario"
- More importantly: best-case scenario
:::
::: {.fragment .highlight-block .smaller}
**Proposition 2.3.**
Expand Down Expand Up @@ -1186,7 +1183,7 @@ Characterizing multiplayer free-form bargaining
- Almost no structure
- Group-level unrestricted **chat**
- An interface for proposing and accepting allocations
- No binding decision until the very last second
- No binding decisions until the very last second
:::

::: {.fragment}
Expand All @@ -1196,7 +1193,7 @@ Characterizing multiplayer free-form bargaining

::: {.fragment}
- We test whether:
- Outcomes vary as we would expect, based on bargaining power
- Outcomes vary based on bargaining power as one would expect
- Certain CGT solution concepts provide good predictions
:::

Expand All @@ -1211,22 +1208,22 @@ Characterizing multiplayer free-form bargaining
:::: {.smaller}
::: {.fragment}
- Early unstructured bargaining papers (1950s-1990s):
- e.g., @Kalischetal1952, @Maschler1965, @NydeggerOwen1974, @RapoportKahan1976, **@MurnighanRoth1977**, @MurnighanRoth1978, @Micheneretal1979, @MichenerPotter1981, **@LeopoldWildburger1992**
- @Kalischetal1952, @Maschler1965, @RapoportKahan1976, **@MurnighanRoth1977**, @MurnighanRoth1978, @MichenerPotter1981, **@LeopoldWildburger1992**
- Face-to-face bargaining, different experimental standards
:::
::: {.fragment}
- Free-form bargaining
- e.g., @Galeottietal2018, @HossainLyonsSiow2020, **@NavarroVeszteg2020**
- @Galeottietal2018, @HossainLyonsSiow2020, **@NavarroVeszteg2020**
- Almost always bilateral
:::
::: {.fragment}
- Multi-lateral bargaining
- e.g., @MonteroSeftonZhang2008, @MitsutsuneTakanori2014, @TremewanVanberg2016, @chessa2023experiment, **@ShinodaFunaki2022**
- @MonteroSeftonZhang2008, @MitsutsuneTakanori2014, @TremewanVanberg2016, **@ShinodaFunaki2022**, @chessa2023experiment
- Structured or semi-structured
:::
::: {.fragment}
- Fairness views in bargaining
- e.g., @LuhanPoulsenRoos2019, @Schwaninger2022, **@ClippelRozen2022**
- @LuhanPoulsenRoos2019, @Schwaninger2022, **@ClippelRozen2022**
:::
::::

Expand Down Expand Up @@ -1328,12 +1325,16 @@ How to divide the value between the players?
- Even in the dummy player treatment!
- $Y=10$ and $Y=30$ treatments still look similar
- In the $Y=90$ treatment
- $A$ only achieves significantly higher by excluding one small player (@sec-timing)
- $A$ only achieves significantly higher payoff by excluding one small player
- Neither efficient nor stable
:::

::::

::: {.crossref}
Timing of agreements: @sec-timing
:::


## Testing the axioms {#sec-axioms}

Expand Down Expand Up @@ -1384,13 +1385,15 @@ Details: @sec-axioms-appendix

::: {.crossref}
All chat messages: @sec-chat-topics-all

Example chat messages: @sec-chat-example-stability
:::


## Main takeaways

::: {.fragment}
- Lots of **equal splits** in all treatments, but considerable **heterogeneity**
- Lots of **equal splits** in all treatments, but considerable **heterogeneity** between participants
- Heterogeneity in fairness concepts?
- Norms established in early rounds?
:::
Expand All @@ -1399,7 +1402,7 @@ All chat messages: @sec-chat-topics-all
- No bargaining power advantage when there is no profitable deviation
:::
::: {.fragment}
- Both **overestimate big player's share**
- Both **overestimate the big player's share**
- They do not capture all relevant fairness considerations
- Combining other-regarding preferences and CGT might be promising
:::
Expand Down Expand Up @@ -1670,15 +1673,13 @@ $$

## Utility function {visibility="uncounted" #sec-utility-function}

::: {.incremental}
- Follow @anderson2021hybrid
- Unit mass of customers, each choosing one product maximizing $$u_{ij}^T = v^T - p_i^T + \mu \varepsilon_{ij}^T$$
- $T \in \{P, F, 0\}$
- Unit mass of outside options at price $p_i^0 = 0$
- $v_T$: value of the product
- $\mu$: degree of horizontal differentiation
- $\varepsilon_{ij}^T \sim \mathrm{Gumbel}(0, 1)$: taste shocks
:::

::: {.crossref}
🔙 @sec-demand
Expand Down Expand Up @@ -1864,26 +1865,36 @@ $$
:::


## Chat – Stability-based reasoning {visibility="uncounted"}
## Chat – Stability-based reasoning {visibility="uncounted" #sec-chat-example-stability}

::: {layout-ncol=3}
![Y = 10](/out/figures/chat_excerpt-2702-2707.svg){.chatlog}
![Y = 90](/out/figures/chat_excerpt-6846-6847,6849,6851,6853,6855,6857,6859.svg){.chatlog}

![Y = 30](/out/figures/chat_excerpt-5640,5647-5648,5660-5663.svg){.chatlog}

![Y = 90](/out/figures/chat_excerpt-6846-6847,6849,6851,6853,6855,6857,6859.svg){.chatlog}
![Y = 10](/out/figures/chat_excerpt-2702-2707.svg){.chatlog}
:::

::: {.crossref}
🔙 @sec-chat-topics
:::


## Chat – Fairness-based reasoning {visibility="uncounted"}

::: {layout-ncol=3}
![Rejecting small offers](/out/figures/chat_excerpt-7894-7901,7906.svg){.chatlog}

![Equal split](/out/figures/chat_excerpt-7052,7054,7057-7063.svg){.chatlog}

![A gets a bit more](/out/figures/chat_excerpt-7590-7596,7598-7599.svg){.chatlog}
:::

![Rejecting small offers](/out/figures/chat_excerpt-7894-7901,7906.svg){.chatlog}
::: {.crossref}
🔙 @sec-chat-topics
:::


## Chat – Dummy player treatment {visibility="uncounted"}

::: {layout-ncol=3}
Expand All @@ -1894,14 +1905,23 @@ $$
![Appeal to pity](/out/figures/chat_excerpt-1371-1376.svg){.chatlog}
:::

::: {.crossref}
🔙 @sec-chat-topics
:::


## Chat – Feedback about experiment {visibility="uncounted"}

::: {layout-ncol=3}
![Having a chat](/out/figures/chat_excerpt-6508-6509,6511,6513,6524,6527,6528-6529.svg){.chatlog}

![Bargaining time](/out/figures/chat_excerpt-5501-5508.svg){.chatlog}

![Payouts](/out/figures/chat_excerpt-286-291.svg){.chatlog}
:::

![Bargaining time](/out/figures/chat_excerpt-5501-5508.svg){.chatlog}
::: {.crossref}
🔙 @sec-chat-topics
:::


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