Example

Example

For instance, suppose that very old jewels have been stolen in a museum, and we know that the suspects are Peter, John and Mary. Thus $\Omega = \{Peter, John, Mary\}$ .

Two police inspectors collect testimonies, and get the following information:

For the first inspector, among 10 witnesses:

5 think that they saw a man ( $m_1(\{P, J\})= \frac{5}{10}= 0.5$ ),
2 think that they saw a fair person ( $m_1(\{J, M\})= \frac{2}{10}= 0.2$ ),
3 express no opinion ( $m_1(\{P, J, M\})= \frac{3}{10}= 0.3$ ).

For the second inspector, among 10 witnesses:

6 think that they saw Peter ( $m_2(\{P\})= 0.6$ ),
4 express no opinion ( $m_1(\{P, J, M\})= 0.4$ ).

All those evidences make it possible to assess, for each inspector, the degree with which it is credible and it is plausible that each person or group of persons is suspect (see Table 44). It is then possible to aggregate the information collected (m₁₂).

Table 44: Example of body of evidence over the reference set of suspects $\Omega = \{Peter, John, Mary\}$ .

Events	$\emptyset$	{P}	{J}	{M}	{P, J}	{P, M}	{J, M}	{P, J, M}

Mass m₁	0	0	0	0	0.5	0	0.2	0.3
Bel₁	0	0	0	0	0.5	0	0.2	1
Pl₁	0	0.8	1	0.5	1	1	1	1

Mass m₂	0	0.6	0	0	0	0	0	0.4
Bel₂	0	0.6	0	0	0.6	0.6	0	1
Pl₂	0	1	0.4	0.4	1	1	0.4	1

Mass m₁₂	0	0.54	0	0	0.23	0	0.09	0.14
Bel₁₂	0	0.54	0	0	0.77	0.54	0.09	1
Pl₁₂	0	0.91	0.45	0.23	1	1	0.45	1

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